One of the reasons Romney lost the presidential election was his fear of losing independents and moderates if he attacked Obama. But he attacks Trump with some heat, leaving one to ask, "Who is he NOT so afraid of offending?"
Well, that would the Trump supporters and the anti-GOPe. And why is he not afraid to offend them? Because he thinks their vote is the property of the GOPe and they are wielding it from ignorance. Don't worry about attacking the voters' choice, they aren't going anywhere. It's the arrogant high-handedness of those-who-know-better and it comes off as patrician as the New Yorker magazine's Eustace Tilley.
McCain was so afraid of offending the middle and the so-called “moderates”, that he practically all but said “Vote for Obama, he’d be at least as good a president as I would be”. And all the white guilt voters took him at his word.