...or the relative value of Google's ads is decreased and advertisers take their money elsewhere
In part, I've been badly spoiled by another forum I participate in that heavily moderates tone (and tries to separate it from content). I wouldn't have guessed it, but it turns out that low-effort intellectual dishonesty and rank stupidity of the sort that annoy me here correlate pretty well with emotional incontinence, which means that the occasional low-quality commenter that pops up on that forum gets washed out pretty quickly.