He has debated Richard Spencer, the literal founder of the alt-right. I think it is unarguable that he has platformed the alt-right by so doing - the question is, will he be cancelled for doing so?

This includes both social cancellation (e.g. Destiny complains he can't secure debates, is disinvited from venues etc. due to him being no-platformed) and platform cancellation (e.g. YouTube bans Destiny). It does not include demonetisation.