Couldn't YouTube have adopted Reddit's quarantine concept? (Ignoring for the time-being the inherent tendency of such a concept being used to drive out dissent as happened with Reddit with respect to fringe conservative voices)
The platform existing for everyday people to disseminate their views is secondary to using user-submitted content as a vehicle for advertising revenue. Another way of thinking about it is that the popular content subsidizes the not-so-popular content.
As a corollary: The more popular your content is, the more advertising revenue it needs to bring in. There was even some controversy somewhat recently about this very thing.