Yeah, that one I don't agree with Hummel on whatsoever. If this were the NBA back in the 90s, yeah, that'd be considered a hard foul. But this is college basketball in the 2020s. It's a really bad and clear-cut flagrant foul. Even if you argue he's making a play on the ball, which quite frankly is giving that foul way more benefit of the doubt that it deserves, he missed by multiple feet and hit a guy with an otherwise open dunk directly in the head, hard. Based on what the B10 has called flagrant fouls in recent years, I think the play is on the very far side of flagrant 1 if not a flagrant 2 outright. Plays like this are what the NCAA was trying to get out of the game because of how dangerous they are.
I'd personally have called this a flagrant 2. He can say he didn't intend to hit him, but you can't wildly swing in the vicinity of a player's head like that. Clear fragrant and one of the worst flagrants I've seen in B10 play in the past few years. Should've been straight ejected.