Also let’s not forget that Steve wanted to be part of the army because it was the only way he could actually make a difference and stop the violence and slaughter that happened overseas, not because he wanted to brawl and kill others. Like he put it in the movie “I don’t want to kill anyone. I don’t like bullies, I don’t care where they’re from”.
And in that same movie he went in against orders and went to save over 400 men held in an enemy camp, who would have been killed had he not come for them. He defied orders of the US army to save people, so we know he isn’t just blindly following orders either, or putting up with the army telling him who he can and can’t save. The point of his character is that he helps people in need, the army was just a means to an end. Steve joining the army and putting on the suit is generally in the service of other people or the greater good, not personal gain or fame or glory or whatever.
His ambition wasn’t to join the army. That was just a means to an end. His ambition was to protect people and make the world a better place, and by signing up he could do that.
“There are men laying down their lives. I got no right to do any less than them. That’s what you [Bucky] don’t understand. This isn’t about me.”
Steve is a progressive person, that’s not fanon or a headcanon, it’s literally what he stands for. His whole character (like @cardentist and @apersnicketylemon explained) is about protecting minorities and those in need, as he was created by people who needed that. Who needed a hero who would give them hope, who would sock Hitler in the jaw and save the people in need.
