It wasn’t reasons unknown—on Kelly’s first day back she and her anti-Trump guest snickered while they misrepresented Trump’s position on immigration.
He’d been led to believe that the Fox cease fire would be honored, and there she was mocking him as soon as she was back on the air.
But yeah, he should have been more careful with, particularly, retweeting a bimbo reference, when he’d already been roasted for doing the same thing a couple of weeks earlier.