You have no idea if his second semester was a farce. That's total speculation. He may not have known he was leaving until after the team went as far as they did in the tourney. If they're eliminated early, maybe he makes a different decision. These guys change their minds all the time. Will Fuller comes to mind.
You need talented guys for those "exciting" seasons, and that's always going to cause a conflict with players who want to go pro. The guy wasn't in trouble while at ND. He didn't flunked out. He didn't get a DUI or have problems with the law. Much ado about nothing. I assume you feel the same about football players who leave after their junior year?