It's because you specifically are very obviously a liar. You didn't spend three years being shouted at in university, it's a crazy claim.
Are there shitty leftists, yes, leftists are people and people have flaws. The idea that the entire community is just people telling at white guys is a fabrication. It's a fabrication pushed by people who want to excite hate on the internet. That's why the conversation only ever happens on the internet. Make community and find help.
They also claim to be persecuted for their hobbies. I think they have some personal issues that makes them feel persecuted all the time. I have a friend like that, it's exhausting. Everyone really likes him but he thinks they don't. I think it's just internalized hatred.
I tried to talk to him about the way he talks about women. "You say things like women behave like this, or all women are like that, or I won't have women on my boat anymore because they don't listen". To which he complained I called him a piece of shit and that I obviously hate him. "I love you dude, it's harming your relationships and making your life harder, it's a thing you can work on, all you have to do is hear what I'm saying."
He can't do that though. He's just always already on edge because he constantly feels like he's being judged and he still doesn't realize the judging is coming from inside the house.