The funny thing is once the election was over, suddenly a slew of articles came from WaPo talking about how Bernie may have had gotten short changed from the primaries and how they may have affected the election, be it preventing him from facing Trump or dividing the Democratic voter base. Like, only NOW does this newspapers care about Bernie. A lot of supporters for Sanders won't forget the treatment he got from the Washington Post.
Plus, in the case of Trump, his anti-establishment rhetoric may have meant it worked in his favor to not get endorsements from the media elite.