If his head and heart were not in it anymore, then staying around and taking snaps away from those who want to play isn't doing service to his team either. He came here to get an undergraduate degree, and play football. He did both. He's not obligated to continue to play just because he can. I'm sure this was probably an extremely difficult decision for him to make, considering he went through almost all of spring ball before making it.
It certainly would be nice to still have him around, but only if he was 100% committed. If he isn't, time to move on. Good luck to him as he has made a life decision, and isn't putting his faith and all his marbles in the hope of playing in the NFL like too many players do.