I don’t think it’s the content of what he is saying that his supporters are drawn to. Trump has succeeded in positing himself as a victim of the “woke left” and the “establishment”. His entire project relies on this vehement opposition. He actually needs the political correctness because his opposition to it is what sustains him. There are theoretical studies of this, like for example Todd McGowan theory of left and right enjoyment. The enjoyment of the right is this enjoyment of transgression, the utterly childish thing of “I am gonna say exactly what you tell me not to say”. The more dumb shit he says the more it goes up. This is what some leftists do not get. You’ll never defeat Trump by showing that he said something bad and "transgressive ". This is exactly his appeal. The right succeeds in making a weird move. They cast the leftist as the “parent figure” that’s out there trying to steal your enjoyment. “You can’t say anything anymore these days”. Ironically the right is the moralizing position, but they succeeded in casting the left as this moralizing figure and we play right into their hands. The early leftist transgressive “hippy” figure has been replaced, in popular imagination, by the uptight professor telling you what you can and can’t say, and you saying it anyway and bonding with the class through that very prohibition.