Trolls can only enjoy communities where they get attention. If they post low-value content and get no response at all, they soon tire of the work of thinking up and writing posts. The only way they can then continue is through flooding copypasta, which is one of the few cases I'd expect moderators to intervene.
With regard to newbs, they will of course be able to post and gets Qs answered graciously, but naturally get little traction if they persistently post errant arguments that don't advance discussion (taking that lack of traction it as a cue to lurk more for a while).
In short, everything takes care of itself if the culture is geared toward a high density of valuable content, which so far it is. (And to be clear, even if culture declines, moderation is not the answer but rather leading by example.)