> this odd pressure against people who might be hesitant to sleep with someone U=U always feels uncomfortable and manipulative to me.

That's because you're a probably a normal and well-adjusted person with no chips on their shoulder.

> I see it a lot around the internet.

If you think the population's attitudes are what is visible to you on the internet, you'd be wrong 100% of the time.

Turns out, shaming people into silence on the internet does not change their minds about anything.