I hadn't heard that - my understanding was the problem was that G+ elevated the pseudonymous trolls too high in the ranking - because they're part of the G+ "culture", G+ treats them and their upvoters as popular power-users and gives them premium placement.

But either way, in any other general-purpose comment-engine, the host of the channel/blog/page/whatever would be able to allow/deny anonymous or pseudonymous users. AFAIK, all YouTube allows is whether you want to allow or deny comments in general.