Trump is trying to control and manipulate news about himself, saying CNN is fake, so his followers and voters they believe him and tune out the so called fake news. and wallah! it lowers CNN ratings. but the truth is Trump doesn't like to hear anything negative about him from the news media. So he calls it fake. He's just a big vocal insulter of things and people he doesn't like and perceives them to be his enemies, when in fact they are not! they are just truth seekers of the Good, Bad, and Ugly world we live in today.
Trump has been calling out the likes of CNN since the 1990s at least. It is nothing new unless you are ignorant of the truth.
See video: Trump Schools CNN Reporter in 1990 - Then Drops the Mic - Literally