It's a very fine line I think. When you represent a university in a prominent role like an athlete, cheerleader, even band members, etc. - you are in a different position than a typical stupid. Actions and words can have consequences as it relates to that position. (I definitely appreciate that they didn't do anything to Pitino, even with morality clauses in contract). I've definitely heard of athletes, cheerleaders, and band kids being suspended (from position, not school) due to actions and words. I don't think that is an infringement at all - they have certain standards as representatives in their roles.
Now, trying so suspend her from school would be a whole other issue. Unless it violates specific code with regards to harassing or threatening another student or staff, then free speech is pretty broad. Plus, it would be difficult to enforce such things with 23,000+ students.