OP, I think you should think long and hard about what you consider "sex-adjacent", and then take the broadest possible interpretation of it. And then realize that people who are actively working to divide and destroy the queer community are going to seize that broad interpretation if you give them an inch.
So maybe you say, well, wearing a bondage harness is sex-adjacent (it's not - lots of bondage involves no sex or nudity at all - but okay.) Wearing a collar is sex-adjacent (again, it's not - it might denote a particular type of relationship dynamic, but that relationship might have nothing sexual about it. Or it might just be something the person finds aesthetically appealing.) Maybe wearing a fursuit is sex-adjacent (is it only sex-adjacent if it's at Pride, or what if it's at a sci-fi convention?) Maybe dressing in leather is sex-adjacent (again, is it just sex-adjacent if it's at Pride, or what about at a motorcycle convention?)
What about drag? Maybe you, if you are a generally reasonable person (and I am trying to give you the benefit of the doubt on that), might waver there. Maybe drag isn't inherently sexual to you - but some people will absolutely interpret it as sexual or kink-related, and are already actively lumping it in with "things inappropriate for children to see." What about other types of visible gender non-conformity? What about wearing skimpy or form-fitting or revealing clothing? I mean, would people really do that if they weren't trying to look sexually attractive to other people? What about people with piercings in places other than their ears or nose? Like, why would you have a tongue piercing or nipple piercings if it wasn't sexual? What about t-shirts with slogans on them or people holding signs that talk about sex in some way, or use crude terms? A child could read that!
I also ask you to think about whether you're applying certain standards unevenly. Are you equally concerned about children at Mardi Gras, which often has public nudity (flashing tits in exchange for beads) as a component, but is not solely and expressly queer? Are you concerned about children seeing sexual content if their parents decide to take them to a PG-13 rated movie? Is that your decision to make on behalf of those parents?
You need to realize that "no kink at Pride" people are aiming to get a wedge in the door to progress to "nothing that offends the mainstream at Pride" or even just "no Pride at all if those deviants can't behave properly in public." This is not idle speculation, this is active observation of what has happened in the past and what Pride was specifically organized to fight against.
People going to Pride parades consent to seeing the type of things that you see at Pride parades. Parents who take their children to Pride (of which I am one) are making the same type of choice as parents who take their kids to a PG-13 rated movie. They are consenting on their behalf to see things that might include nudity, sexual content, crude language, etc. and they, as parents, are putting themselves in the role of answering any questions their kid might have about what they see. People who don't want to see those things can go to other events - because the idea that the only options are "huge flamboyant kinky pride parade" or "nothing" is false. As others before me said, if your local queer community is big and active enough to have the huge flamboyant parade, I 100% guarantee it also has other options available for queer youth and people who might not participate in huge parades for any number of reasons (noise sensitivity, introversion, mobility issues, etc.)
Finally - why is it that people who have these "concerns" always only show up to yell about it online in June? If they care so extremely strongly about how Pride operates, where are they the rest of the year when people are putting the work into organizing events and fundraising and booking facilities? Planning Pride events takes a huge amount of energy and effort and goes on year-round. If it's so important to them, why aren't they turning out at those planning meetings and getting involved in helping build the kind of community they want? Why aren't they saying "I wish there were more kid-friendly events during Pride, or more resources for queer teens year-round, so how about I help organize that?"
They aren't doing that, they are just yelling about it online, which should be a big fucking clue that what they want isn't really "more queer-friendly spaces for kids", but to sway public opinion (back) into thinking "Pride is just a bunch of perverts." They are trying to exercise control and sanitization over a community that is big, diverse, and non-normative. They are actively working to divide and destroy the queer community. And conceding even a single inch to them is a very dangerous precedent.