Cruz would not have had to act “a little like a maniac” if he hadn’t been suckered by McConnell in the first place.
He never called Cruz a maniac for opposing McConnell. He called out the way in which Cruz started his senate career and questioned the effectiveness of such an approach. You can oppose someone without calling them a liar. Trump simply thinks his negotiating tactics would have worked better than Cruz’s attitude. That has nothing to do with issues or supporting/opposing specific people.