By showing off his rod, you mean open carry?
Seems he means (per the story) the guy's "assault weapon". Open carry, a la a politely holstered handgun, in a restaurant is one thing; hauling a good-sized rifle therein is something else. The guy is obviously there to cause trouble, be it agitating for sociopolitical recognition.
Face it: save for very rare scenarios, walking into a restaurant chain carrying a rifle indicates one is trying to cause trouble.
No, I mean showing it off in a manner designed to draw attention to it. Like the small one in the picture in the article I linked to just up thread.