I don't want to "white wash" TotalBiscuit's moments of having an aggressive or arrogant attitude, but the whole deal about his causing "harm" is pretty much bullshit. It is because of that "harm" some people they have the mandate of heaven to say anything you want about him without any sort of moral hypocrisy. In reality, he had one foot in an overblown internet flame war for about 3 to 4 weeks. He made a few YouTube comments and recordings about GamerGate without really attacking anyone directly. I think I saw someone say "he ruined several women's lives", which really calls into the question of what they mean by ruined. Like they still haven't recovered from some dudes appearing in their mentions two or three years ago (not even considering the possibility their tweets might be inflammatory or insulting in themselves)? Twitter is now and has been like that flame war for awhile now, even fairly anonymous people get "dragged" or get quoted with something like "twitter do your thing". Most of the people complaining about these sort of things likely contribute to exactly this kind of dog pilling.
You call something "harm" and you can make it mean whatever you want to whatever degree you want. YouTubers, pedophiles, and war criminals all cause "harm", so there you go. (note: when a dumb gamer gives a hot take on Battlefield V's one-armed female protagonist and gets spammed mean messages by a hundred mad dudes is not harmful tho, just because).