If he had re-tweeted genuine videos of Muslim atrocities, there would be no problem.
Recently Trump re-tweeted posts from a minor British Fascist party. Not sure how big a news this was in he US, but as it was one of our fascist parties, it was big news here in Britain (although a very minor political party). There was a question about it on a news quiz on TV, with debate on the fuss made in the media about the incident. After that the host was supposed to read from an autocue "After all that furor - Donald Trump said.......". Unfortunately she misread it as "After all that - Führer Donald Trump said...."