The concept is simple. The "fake news" meme gives tacit permission for any trumple to dismiss out of hand, without factual refutation, any reporting that forces them to challenge their preconceived beliefs.
Ironically, many of those beliefs are based on demonstrable falsehoods reported by their chosen media sources.
How does one convince a trumple that a falsehood is a falsehood? It's virtually impossible since any factual support used to refute a demonstrable falsehood is immediately disregarded as "fake news."
The construct is perfect for someone, like the Orange Fraud, who wants everything he says to go unchallenged among the minions.