I once had a student try the same racial angle as well. They had been doing poorly in class because the papers they were turning in were awful, and, really, it's partially the university's fault for letting them get that far with those writing skills.

Anyway, they finally turned in a paper that sounded great! It was also plagiarized.

They wrote a letter to the dean, who called me into the office, and we both sat down trying to decipher what the student had written, because it made no sense. It was ironic in some ways that the student's own complaint basically became evidence against them.

I felt somewhat bad for them, even when they were aggressive, because, like I said, and like I told them, I think the university let you down by not giving you the skills you need to be successful...