He calls the media fake because they are fake. Hello? They have been making things up about Trump for years now...It's kinda' hard to miss the fact.
You seem to be lumping together things that I count separately. When I say "Fake media" I mean those rags like the National Enquirer which report unsubstantiated gossip, wild conspiracy claims (like UFOs), and occasional items that are, indeed completely made up, yet they know how to get around libel laws and avoid lawsuits. On the other hand, the "mainstream media" generally are reliable, although it is true that they often betray a partisan political bias and occasionally are caught publishing things that violate their own guidelines. Well-known reporters
have been guilty of journalistic misconduct, just as Catholic priests, medical doctors, police officers, and other respected professions have had to deal with "bad apples" from time to time. But I cannot go along with the idea that the New York Times is no different than the Enquirer. Or that Fox News is a propaganda machine for the Republican party.
As far as the mainstream media "making up" things about Trump, the first things I think of are claims he has made which the media have disproved. He said the crowds at his Inauguration were record-setting. The photos showed crowds much smaller than previous inaugurations. He said he won the election by a huge margin. He actually won less than half of the popular vote, and his electoral margin was solid, but he did better that only two of his predecessors since 1972: George Bush (twice) and Jimmy Carter. Everybody else--Obama, Clinton, Bush Senior, Reagan, and Nixon--won more electoral votes than Trump did. And I remember the times he said "I never said that" when it was right there in the recording.
Trump famously tweeted "“The FAKE NEWS media (failing @nytimes, @CNN, @NBCNews and many more) is not my enemy, it is the enemy of the American people. SICK!” early in his Presidency, on February 17, 2017. That was not a responsible tweet, or a credible one.