So I realize that a lot of people might take this response in bad faith, and while I don't have a catch-all answer to the problem. I do want to state a few things I've seen and that I fear we in the left are chronically bad about. I genuinely hope that people won't view this as some ignorant idiot running their mouth; and rather as someone who's looking to help, because what I'm going to ask of you sounds a little accusatory.
A big thing is that you have to stop with the generalization. I've heard people say "but they do it" and "but it IS most of them" and such. I get it, I get it but you can't say "Cis, Straight, White Men are bad" and then expect the good Cis, Straight, White Men to still stand up for you. I've always been told "but the good ones won't care!" Yes, they will.
I was once told by a Rightwinger on a forum that "the Left are a powerful force in converting people to be conservative." When I asked him about what he meant exactly; he explained (with the use of far too many slurs and insults I'll be omitting) that essentially when otherwise Left-Leaning individuals see the way Leftists talk about them or people like them, it's very easy for Rightwingers to sweep in and basically say "we're not going to judge you like that." Of course they hide the fact they will judge you in other ways, but for that moment; they are a beacon of shelter from the otherwise very loud mob of Leftists who would deem you literally the most inherently bad person for being... a cis man.
Am I saying you have to go out there and start forgiving every bigot, humoring every fuckboy; stop holding sexists accountable for their bullshit? Absolutely not. In fact, what I'm asking you to do is stop firing a shotgun at a target that can only be hit properly with a sniper rifle. I'm asking you to stop giving the bad actors a scapegoat. I'm asking you to be specific.
If you take a young man, who doesn't have any concept of things like gender identity, the patriarchy, homophobia, etc. You take that young man and you look him in the eyes and you tell him:
"Men are a disgusting and violent gender, men do not deserve respect. The only good man is a fictional man. All men deserve to be treated poorly, women shouldn't have to put up with men. Cis men are the worst. Straight Cis Men should go to hell."
He's going to become a conservative rightwinger, because at least they won't hate him for being a man. They'll just hate him for being the wrong kind of man. It's easier for that man to seek acceptance through forcing others to be below him, than for him to accept that he is inherently a problem. If you instead literally word it as:
"Sexists and bigots, who would view women as nothing more than objects are disgusting. Anyone who would look down on, and see someone as lesser because of their race, gender identity, or sexuality does not deserve respect."
Well now he's not a target. Because he doesn't see women that way, he doesn't have racist thoughts; he's not currently a bad person and you're not talking about him. Now I know that a lot of people say "but I'm NOT talking about people like that!" I know that, you know that; you know who doesn't know that? The young man who's reading your posts, the young man who hears you at the store, the young man who read your forum response 3 months ago. What they see, plain as day is "men are a problem" and they're going to seek shelter from that.
Unfortunately for everyone involved; the shelter they end up finding so many times is conservative rightwingers. There are tons of people you can hear talk about this on youtube and forums, people who got indoctrinated because they would rather be praised for being a man than hated for it.
Now you might not talk this way, a lot of people don't; but a lot of other people DO. I see a lot of "the only good man is a trans man" or "the only good man is a fictional man" type posts, and even if you want to say it's just a meme or it's all a joke. You need to understand that when you speak generally, a man, especially a young man is going to see that and react to it. It's going to shape their idea of how the Left, who you represent to them whether you want to or not; see them.
If a young man who currently is unaligned on either side of the political spectrum sees a bunch of gay and trans people shitting on men for simply "being men" and not for the patriarchy, not for the sexism, not for male privilege and all that. Not actually educating anyone, not speaking out about the injustice; not discussing toxic masculinity or anything that may even shine a light on the issues people face. Just saying "men suck" and leaving it at that. Only to then see a bunch of Rightwingers saying all those gays and trans people are stupid and they are bad people and they hate men for no reason. That young man is going to make a no-effort decision in that moment to side with the people who do not openly hate him.
It's genuinely that easy for someone to become indoctrinated. Once they're in, they're rewarded for thinking less, promoting the ideals that promise them a higher spot on the social ladder; and generally following the mentality that Leftists are bad, and Rightwingers are good. They keep digging themselves into that hole trying to find a place they belong, somewhere they won't be hated; somewhere they don't need to feel guilty and wrong for just being who they are. Until they learn that the Right also thinks they're bad and wrong, they're a "beta" because they haven't fucked someone yet, they're a "soyboy" if they're not benching 200 pounds, making six figures, and banging a new girl each week. So now the urge for acceptance has shifted. Being a man means nothing if you're not "the right kind of man" if you're not an alpha, if you're not a sigma male then you're not good enough.
Go figure now they start viewing women as objects. That's not a woman, that's a ticket to not being a beta virgin anymore. She can be bought, she can be manipulated because he's an "alpha" he has money, he has control; he's a man. He's been taught all of this, he's been taught that "bitches don't matter." He's been told that working out and having money can get him any woman he wants. He's been taught women are dumb, that they're materialistic; that they don't matter outside of being a quick fuck. If someone tells him off, or doesn't like him it's because "she's a crazy bitch." I was once told "men don't have friends, men have competition." This is how they're taught.
So now you approach this man in some attempt to help him understand the faults in his ways. The problem is he's been convinced for the last so many odd years that by simply being a Leftist, or by being gay, or by being trans; you're wrong. Before a single word leaves you mouth. Because "all Leftists are special snowflakes who just get triggered by everything." Which unfortunately the internet has "proved" to him because of those videos of gay people screaming at cameras, or posts that generalize all straight/white/cis men to be bad people.
Again, this isn't some catch all solution. It's not going instantly turn the tide or something, but you have to stop using general terms. Be specific; don't say "men" say "Sexists" if what you mean is "sexist men" then say "sexist men." Because when you just say "men" you do imply "all men, including you; the man reading this." Whether that's what you mean or not. I don't believe that men are inherently born with a want for things like sexism and racism. I really don't believe men are some inherent evil born with bad intentions. I believe it's a combination of the way the popular culture tells them they should be something great; and the way the Left tell them they're a horrible person for how they were born. That's a fast track for becoming a "Crypto Hitler."
I cannot tell you how many genuine conversations I've been able to have with Rightwingers, where I've been able to sort of get them to see my side of things even just a little. Because I didn't point a finger at larger audiences. I was talking to a man on a forum just a few days ago about the inherent issue of sexism in an abortion ban. I made sure to use the word "sexists" and the word "men" as separate entities. When I was discussing how men have bodily autonomy that women don't, I would say just that; when I mentioned that sexists want to control a woman's body I would also say just that. He still mentioned several times "Well I never said I wanted to do that." To which I had to point out to him that I never said he did, I said Sexists did; so if he wasn't in fact Sexist then the shoe doesn't fit.
My goal in all of that was to absolve him of blame; but only so long as he didn't fit the bill for the sort of people who deserved the blame. I let him see it as a matter of simple fact. No different than saying "if you didn't shoot this man then you're not the murderer." I didn't say "everyone with a gun shot this man and therefore everyone with a gun, including you; is in fact the murderer." Because doing so would cause nothing but argument. Rather I treated the whole thing as though he couldn't have possibly been at fault right? By the end of it he came out of it saying that abortion still goes against his religious beliefs; but that he can understand how it's specifically a women's issue; and how there should be further discussion about the effects of abortion as a treatment that could potentially save lives. Crazy how that works right? I got a Rightwinger to admit that hey, abortion isn't an issue men should be speaking on. All because I ensured that he didn't feel as though I was pointing a finger specifically at HIM as a man, for being the problem; and instead let him come to the conclusion of whether or not he specifically fit the mold of a "sexist" or a "man." He told me that I was a lot smarter than "those autistic leftists" but he never knew I in fact am an autistic Leftist. That's literally just because in his mind he knows what an "Autistic Leftist" is, what they will say; how they will act, how they'll react. By not being that stereotype; he couldn't just label me some buzzword and write off what I was saying. In his eyes I was a man with a wife and was merely concerned over the safety of our wives and daughters.
Sometimes that's what it takes to make someone see things your way, if I explained to him that I'm a pansexual genderfluid individual who never intends to have children and just believes women should have the right to bodily autonomy for the sake of bodily autonomy the same as cis men have; well he'd probably write me off immediately.
I'm not saying you have you hide who you are, I'm not saying you have to appeal to their bigoted whims and humor their insults. However I am saying that you need to conduct yourself in a way that's going to show young men that you care about them too. That even the young cis white straight men have a place in a Leftist society; that they won't be hated for simply being true to themselves, how they identity; and how they love. That what we want is equality for everyone; and specifically what rights they have for simply being those things, that the rest of us don't for simply being who and what we are.
tl;dr We can save a lot of young men from becoming Crypto Hitlers if we actually stop talking about men in general like they're already Crypto Hitlers.