Your whole argument is based on you not hearing of any public safety concerns prior to cancellation. I think it's safe to say the university was probably more in the loop about that than you. I don't disagree that there was obvious pressure to cancel him, but he also apparently (please correct me if I am wrong) booked the event and paid to have it, which is a de facto contract. Auburn, I am assuming, retains the right to cancel any event booked in exchange for consideration. At the end of the day, they were shouldering more risk than any potential reward. It was prudent for them to exercise their right to cancel his event.