Oliver Burkeman discusses this tendency in The Guardian, exploring how these discussions essentially devolve into binary oppositions of ideology with no real chance for actual discussion.
The following quote effectively captures the incentives that may benefit online news sources from actually starting such debates:
"[The] modern-day “attention economy” could hardly be more expertly engineered to make things worse. News organisations dependent on online advertising constantly face the temptation to make their stories more anger-inducing, and thus more compulsively shareable, than the facts may warrant. And social networks have no business incentive to do anything other than pander to our basest urges. If what you really want to see, as measured by your online behaviour, is posts from obnoxious people being obnoxious – or posts from people you admire mocking other people for being obnoxious – then that’s what you’ll see, even if some higher part of you would prefer not to get dragged into all that yet again."