This may be my confirmation bias, but it does seem that when Republicans are doing well it is described as America becoming increasingly polarised, but when Democrats win it is described as unifying. It's always the other guy who's divisive. Yet when you are a major media outlet aren't you supposed to monitor yourself about unfair slants? Not if your real business model is telling your customers what they want to hear, I suppose.
It's one of the those things that is true either way - or half-true no matter what - but can't be swapped out when things go against you.