He’s one of the (now ex) members of critical role. He was engaged to Ashley Johnson (from critical role, Ellie in TLOU games, waitress in avengers) and they separated with restraining orders because of abuse and general assholeishness.
So critical role is removing him from their content as best as they can so he doesn’t get visibility and such.
Luckily he isn't in the main Campaigns, just side stuff. But the stuff he's in he's usually the main focus (host in Talks Machina, GM in Undeadwood) so it would be impossible to edit him out of those.
No, those are the exceptions I think. I suspect that removing them would have caused too much trouble for the main campaigns, because they would have had to explain that there is missing content and why for anyone who would be watching them for the first time.
tl;dr would be that one of the main actresses on critical role (Ashley Johnston) was in an abusive relationship with this guy named Foster, and Critical Role has now scrubbed every notion of his existence from their page by deleting all videos with him in it.
A valuable lesson on the importance of local archiving and not trusting any online source to stay online.