It's like when you're punishing your children. You might make a mistake with one of the kids, and the other one throws a temper tantrum trying to be let off their punishment because you went easy on the other. If you cave and lessen the punishment you're just making it harder to earn credibility when they deserve to be punished in the future.
Right or wrong, the NCAA can't and should not turn back on Kanter. It's not popular, but giving in and reversing that decision makes the Newton decision even worse. At this point they need to stand their ground and retain the shred of credibility they have left. If the Kanter decision is reversed because of this, it's like a bunch of criminals going to appeal to overturn their convictions on account of one instance of misconduct by a prosecutor.
These situations aren't terribly similar, but even if they were, the worst thing that could happen is for the NCAA to do a mea culpa.