Trump tweeted something. It's not an official statement, and he has repeatedly backed down from things he's said on Twitter. I suspect his tactic is to draw attention via overblown tweets, and then make his actual move after the media storm blows in. In other words, he's taking the "no such thing as bad PR" angle.

This doesn't excuse what he says; if I'm right, he's specifically trying to inflame people's anger toward him for free advertising. All I'm saying is that this explanation fits the pattern.