In my aunt's case, online hate wasn't really an issue. The perpetrator just liked to commit crimes against women. I don't think anything he saw online encouraged him to do that, because he was like that before social media was really a thing. He's 54 and he's been like this since he was young, although obviously he wasn't committing murders then.
I can't say I'm 100% familiar with what you're referring to, but with regard to my aunt's case, it wouldn't have made a difference.