I fully agree, although in my case it's not advertising per se. I'm on YT Premium, I don't get ads as such. But they're still trying to "sell" me engagement, of course. There is very little doubt in mind my that extremist content is maximally engaging, especially for the many people who actually fall down the rabbit hole and get their filter bubble permanently modified.

While YT staff may not actually hold these extremist views themselves, my guess would be they're nevertheless actively pushing it for commercial reasons. Just like it turned out that the supposedly liberal pre-Elon old guard of Twitter had special protections in place that made accounts such as LibsOfTikTok immune to getting banned, I am quite certain Youtube has the same protections for extremist channels that would otherwise run afoul of its T&C on the daily.