>>pg+C6
You do it with the stories, by weighting them manually. You do not do it with the commenters. But there are factions of commenters who are introduced to the site by following stories onto it, and they stay, they promote bad sources, and they inject both politics and a particular inflammatory mode of debate into all the threads.
There are overwhelmingly more people on the site saying quality has degraded sharply --- most of them citing politics as one of the reasons --- than there are people defending it. Also, a close look at the people who do defend the current quality of the site might be instructive.