It wasn't very long ago that Tommie Smith and John Carlos were ostracized for doing a black power fist pump during the Olympic ceremonies.  I guess it doesn't count when Trump brings this same insult to the national anthem up.  Well he's Trump, so he must be wrong, but in this instance he is not.
This is what he refers to, when he says "fake news".  Pretending to be insulted by what he stated is fake/false/B.S.