Whether Lewan went over it...most likely not. The line about Gholston being provoked...like duh, no shit sherlock, of course you were provoked. Usually everyone who throws a punch like that is provoked in some way. You can't use it as a defense that somehow what Lewan did to you made it slightly more OK to punch him like that.
MSU is absolutely clueless how to handle discipline. But I bet you Dantonio thinks they're the poster child of discipline after they were forced to suspend Gholston.