By "gamergate harassment" I mean the campaign of criticism and harassment that was primarily focused on several prominent women in the gaming/media industry from about 2014-2015. Thunderf00t was particularly focused on Anita Sarkeesian, making dozens of videos about her and bringing her up frequently in unrelated videos over the course of multiple years. He helped create a climate where people felt the need to threaten and doxx others because they were feminists and "SJWs".

I certainly agree with your view of opinion channels, take everything with a grain of salt unless it has a source. Even then, make sure the source is legitimate and not manipulated before assuming it is correct. I do not mean to say he is wrong about everything, just to apply some extra skepticism to his opinions and ideas. Particularly when it comes to stuff outside the scientific sphere.

hbomberguy made a good video about some of the stuff he closer to when it was happening. It is primarially focused on Thunderf00t's reactions to the Ghostbusters trailer, but it does go a bit into the gamergate stuff. It gives a good idea as to what kind of videos he made on gamergate. It's largely opinions though, so be sure to approach it critically as well.
https://www.youtube.com/watch?v=SpgBkpb7xlU