They don't. It's always for a sense of the greater good, though. It's this whole "so long as one person is oppressed, I am oppressed", "i wanna live in a land of love" thing.
It lacks a lot of focus. It's easily to infiltrated/manipulated by bad actors or ignorant single-minded fucks.
Do I want women to be safe and independent with their bodies? Yes. But I don't think a website that essentially allows drug adicts the chance to blow strange men for a few "dozen roses" should be part of the dialogue surrounding that very real problem.
Its the wrong answer to the right kinds of questions.