Oh, they would get more than a grievance filed from me! They have no right nor any invitation to voice opinions on personal decisions you made that had nothing to do with them. THE NERVE of that statement is beyond belief. Not only was it unprofessional, but mean spirited and cruel. When that happens to me, I come up swinging (figuratively, not literally, although I could handle that as well.) I would go to the superior of the one(s) that made that snide comment and demand an apology and immediate reinstatement on the grounds that there is no rule against what you did, and that obviously, there is some personal reason that you were dismissed. If you don't get anywhere with them, start spreading the word that the program treated you unfairly and see if you can't get their attention that way.
What Wisher said! I would probably be talking to an attorney. You have invested not just time and effort, but money, into this program, and you are owed. Big time. The comment about your priorities is unthinkable and has not only no bearing on whether you violated a rule not written anywhere, it actually elevates your commitment to the program for which you paid, and to which you have devoted yourself. I am beside myself with anger on your behalf and we've never even met in person!