This depends. First, I wouldn't equate a YouTube personality and the teacher of my children. One's an entertainer, one's a teacher - both influential for sure, but the teacher even more so.
Also, would the teacher say (or preach) their opinion in class? Or would they argue with someone on Twitter? If it's the latter, then I wouldn't actually see any problem.
Sure, Playtonic can do whatever they want like that. And it's valuable to know that you can't say anything without any consequences, but where's the line? Should the ad revenues be cut from his videos? Should Twitter kick him off the platform? Should Google close his YouTube account? Should he be banned from ever working with other's ever again?
Who else should we remove from various places because they have the wrong opinion? Remove all KISS songs from rock games, because Gene Simmons is a Trump supporter? Where's the outrage for Mafia 2 and their inclusion of Chuck Berry songs, considering he was sent to prison for trafficking? Do they want to be associated with that? The list could go on and on and on.
Considering all the promotion he made for them, the initial hype for an eventual sequel to Banjo-Kazooie, and everything that Playtonic has gained a lot from... to then sever the ties with him a few weeks before release. I just don't think that's nice.
Even if he's an evil person with the wrong opinions. I mean, how dare that Iranian boy with immigrant parents have opinions on immigration?