It’s not just the men, it’s the social rituals and expectations that accompany marriage, dating, sex, etc. People internalize those unwritten rules, even when they intellectually know it’s bullshit. It’s the path of least resistance.

Anyway, it’s their choice: some men, all men, whatever. From your (or my) point of view as a man, some women just won’t want to get with you, and they’re not obligated to explain why. That’s autonomy, and whining about it doesn’t change the fact that they don’t have to tell you their reasons. It’s ultimately none of your business. They can opt in if and when they choose, and if they choose not to, get over it.