>It's jarring -- that is, newsworthy -- to see overt sexist or racist remarks with hundreds of upvotes, suggesting at least widespread if not majority support. So, yeah, that fact is going to find its way into many articles.

There is a polarising effect which occurs in these kinds of threads (or communities discussions as a whole): once the vitriol has met a critical mass the more moderate people tend to just avoid the whole thing (not participating, likely not even observing). So all that's left are the extremists who keep perpetuating it.