After he knocked he guy out and took it?
According to a police report acquired by at least two Alabama newspapers, Williams admitted to investigators that he physically assaulted another man "and rendered him unconscious" on campus Monday morning at 3:21 CT at Bryant Hall dormitory. Williams then stole a credit card and used it for several purchases, according to police. The report said it was used at a vending machine.
Say what you will, but using a stolen credit card should be grounds to kick anyone out of anywhere.