I agree that it is problematic and tone-deaf and she shouldn't have said it, given what you said about fetishization. And even more than that, she should not have dug her heels in when a fan challenged her about it.
But I don't think it is at the level of cast members using the n-word-hard-r while in a fight, like Camila and Jordan have done. Or doing blackface.
See what I'm saying? It was wrong. But if MTV is going to fire her for that, then they should say goodbye to other cast members who have said similar and worse things.