He has demanded the firing of a Fox News reporter who confirmed an Atlantic story reporting that Trump disparaged those who served and died in the military

To be fair, he’d been doing his best to get Fox to fire personalities that did anything to displease him for at least a few years prior to the 2016 election. Read Brian Stelter’s Hoax: Donald Trump, Fox News, and the Dangerous Distortion of Truth for how a Fox/Trump feedback loop got us to where we are for a detailed account.