Trump only attacks those who shoot first.
Ex: McCain calling Trump supporters crazie, Megyn Kelly’s blatant smear campaign/debate.
Trump is looking to be chosen amongst a large field,and needs to overcome his current obstacles to do so which are the other candidates. Once he gets the nomination he will focus on other people.
He’s already put Megan in her place once but he’s dragging it up again. That’s not good strategy. Best to ignore her. Big egos hate being ignored.