I don't give a shit if it's supposed to be a joke or not. One, it wasn't a very funny one. Two, he went up to someone, regardless of their status and gave them shit about being at a game cheering for a certain team. Someone just minding their own business at that. Fuck that. Maybe Cusack got fed up with the Cubs? Maybe he always liked both teams but liked the Cubs more? In the end, who cares. Let him go to whatever game he wants and cheer for whoever he wants.