the fact that any would find this offensive besides Da Vinci (for using his work) is simply absurd. The clan picture does not refer in any way to christianity, only the painting of the last supper by da vinci. There are no christain signs or symbols or anything that could possibly find offensive.
the painting is above my picture so you can compare and contrast the two and see my inspiration. If you want to see something that WOULD be offensive search statan last supper on google....
The only reason i can see for people being offended is to get attention :/