I think there are a couple of reasons for that.
Part of it was nerd stuff was cool, and once it wasn't cool any more they wanted to jump ship but have no employable skills. The jobs they can get pay less and are much harder work. There's a length post called geeks, mops, and sociopaths that's well worth a read if you want to see what happened with nerd culture.
https://meaningness.com/geeks-mops-sociopaths
Part of it was gamergate. It's no secret that games journalism was always corrupt, but it went from the occasional magazine shilling a AAA game to full blown sex for favours and gate keeping. Either you kissed the ring and paid the piper, or your career would be destroyed by proxy. Once that was exposed game journalists had 2 options, either admit wrong doing and improve, or go down with the ship to keep the gravy train going for a few more months. They chose the latter.
I could go on but this post is

fftopic: enough already.
For Bob specifically though, he is unique in that he was in the clique but didn't get the benefits. He wasn't being flown to swanky parties in LA, Tokyo, and various other exotic locales. He wasn't getting $200 collectors edition in the mail like even mid tier YouTubers do. I doubt he was getting laid by PR reps, and while I personally don't think he has the nerve or the inclination for sexual assault, he had the opportunity and there's no shortage of people in that clique who did go for it.
Bob is (in part) a product of his echo chamber. He parrots the opinions of other critics uncritically. Mass Effect, Dead or Alive Xtreme 3, and recently Diablo Mobile. The motivation for the critics opinions don't apply to him. Bob is a useful idiot not just in politics, but as a critic too.