Or...OR...they could teach the little twerp a lesson about the consequences of violating cafeteria/school policy. He wasn't just drunk in the cafeteria, he had an open container. The manager had every right to toss him out. Then, the kid got in his face and threatened him. You do not reward that by giving him what he wants. Christ, the lack of discipline in this kid's life is the reason this incident even went down. You punish him by asking him to leave and come back when he's sober. If he just leaves, he doesn't get in trouble, there are no cops, we don't know his name, etc. He escalated it, thus he must deal with the consequences.
Also, who knows if that mac and cheese was even available that day? I remember college dining halls. They had a lot of food on rotation that wasn't even available for days at a time.