There is a massive difference between "being yourself" and the things he was saying. He is a grown adult, and knows there is a time and place for his type of language. It is called being a responsible, professional, employee.
I would fire any of my employees I hear talking that way while on my clock with customers present.
Not when he has presented this character of himself in seemingly everything he's done... how could your employees possibly be comparable to this... your employees are hired to act professionally... this guy was hired for his out of line humor... it's comparable to hire an actor.. like if you hire Tom Green, wth do you think you're gonna get???