Stephen Colbert's monologue about Trump is getting a lot of attention. He certainly pulls no punches with his comedy and with his colorful metaphors––assuming they are actually metaphors.
It does raise an interesting question: how much can actually be said about a public figure, who is the president, without running afoul of libel or slander laws? Quite a lot.
People need to accept that this is what free speech looks like; if they don't like it, then they can stop watching Colbert's show. Colbert Monologue