The whole shirt actually reads "I Love Big Sacks And A Gator D" and Muschamp is just smiling like the nicest guy in the world while the woman is pretty straight-faced. There are a few explanations, which we've narrowed down to (a) he didn't read the shirt and is just naturally charming and amiable, (b) he did read the shirt and appreciates when fans work blue or, (c) he read the shirt, but doesn't know what makes something offensive.
h/t @Goldkamp247