When he said the media was dishonest, he was referring to CNN, WaPo and the mainstream media (excluding Fox News). Anyone who follows Trump know these are the folks he's referring to. If he didn't like ALL of the media, he wouldn't even have a press corps. Reuters isn't really engaging with what Trump's saying.
Are Trump's claims substantiated? I would say, Yes.
During the last election cycle, anybody who knows anything about the DNC leaks, Podesta emails, CNN feeding Hillary questions during townhall meetings against Sanders, Hillary's gliding past the FBI investigations, "bleaching" her email servers (which were under subpoena), Bill Clinton's unprofessional meeting with Loretta Lynch... knows that there's some serious corruption happening at the top of these major news companies.
As a litmus test... the fact that almost every liberal in America is yelling at Trump more than they're yelling at the DNC (and Debbie Wasserman Schultz) shows the state of mainstream media. The DNC sabotaged Bernie Sanders nomination, and he was the only candidate that would have a chance of beating Trump (a very high chance since he had young vote). When the DNC sabotaged Sanders' nomination, and doubled-down on Hillary the loss wasn't just technical––it was a landslide[1]
Mainstream media is really broken in America. There really needs to be a breakup of corporation-owned news companies. It really is a swamp in Trump's idiom.
[1] http://www.politico.com/2016-election/results/map/president