UPDATE: Tom Knighton adds:
The university claims it barred all political signs from the event, stating that they removed a second political poster from the event, and that it was anti-Trump. But Kell [the student] says that there were indeed other signs present during the event, and that they were anti-Trump.
Either not everyone got the message, or one of the two parties here is presenting incorrect information. But considering the current atmosphere on campuses nationwide, and how Trump supporters have a much, much, much better track record of veracity on stories of persecution or harassment, I'm inclined to give Kell the benefit of the doubt.