What case? There isn't case to be made. I don't think it's classless and vulgar. You aren't going to change my mind.
I would not even attempt to change your mind as you are a fool. As an American, you are entitled to your opinion but you should realize that you are part of a very distinct and very small minority.
Here are the unchallenged facts:
1. the IU fans made the chant;
2. it was heard over the tv;
3. a story about it was written in a major New York City newspaper;
4. the newspaper in question is the oldest in the country, founded by Alexander Hamilton, and is located in the largest city in the USA and the central media center;
5. it was described as vulgar in the story and headline; (not just my opinion but that of the author and editor)
6. it was certainly inappropriate, especially since it is reported that the girl's family was in attendance; and
7. it is derogatory and demeaning to the girl in question. It held her up to ridicule and shame for no transgression on her part.
If you think that this makes IU look good and that it is not an embarrassment to the university then you are dumber than I think that you are. My expectation is that the university administration will be shortly made to make a public apology to her and her family for this incident. At least that would be the proper thing to do.