If Rockwell "offends" folks, they are how many decimel points "behind" the zero? .00001%? The Smithsonian is a public funded warehouse of artifacts, and historical items. Let the universities display and "stimulate" debate.
Ask this critic if he can find an artist with the balls to do the same with a statue of Allah? I didn't know ants on Jesus was related to AIDS? It's such a clear correlation.... 
The big point FQ, is Not On Our Dime. There are plenty of private exhibit venues for this crap.
you get me a statue of allah, and I'll make some art for you...
good art will do one or more of the following:
convey a emotion
make you think
"transport" you another place/time.
envoke emotion/memorys
It does not matter what the art is,it could be music, visual, tactile...you name it.