You guys do know that you can blame both of them, right? He was, and still is a loser and she's still an unlikeable asshole. The MC's only saving grace is that he didn't go full Masamune-kun.
1. This is manga and Japanese is weird about gendered language. Why do you think mtl translations fuck up genders all the time?
2. This is manga and they could all be whatever the writer/artist wants them to be
3. Get that shit out of here
If a guy with shitty pants tried to eat your face and scratch you with shitty fingernails, you'd be scared, too. That's like fighting Super Florida Man.