This goes for males as well as females. They see a question regarding a relationship just to bash all men or all women putting everyone in this stereotype. They start off with most guys... or most girls...
Because they are not interested in peoples views or the truth they just want people to support them with their false views. It is easier for them to blame the opposite gender than look at what they might be doing wrong. All it makes them is a massive turn off for the opposite gender.
It's far worse elsewhere (go on Tumblr and see some of the SJW/radical feminist/MRA battles). Some people (well, probably a lot of people) are bitter, or they're carrying other people's bitterness. For other people, it's their cause (wrapped up with how they see themselves).
Activists in general tend to be pretty black-and-white, narrow-focus folks. It gets really bad when you're talking about gender issues, where most of us will never experience what the other gender goes through. There can be a tendency to see only how good other people have it, and only see how bad your own life is, and generalize.
Because sex and sexual topics are what interest people more than anything. Plus, the majority of users here are like around the age of 20. That's one of the most sexual (in terms of interest) parts of life. It's a top interest. That's why we see so many sexual topics here.