I'm mildly amused that a comic depicting various religious figures in a (however weird) sexual act could be considered not safe for work - which seems just a different way to say "Comics like these might offend your coworkers / employer", which .. feels like the reduced, small-scale version of the "crime" the OP is prosecuted for.
It's a harmless picture, a comic, from a satirical magazine. It shouldn't be considered unsafe for work.
If The Onion didn't get in trouble for this one, then the US is safe. Cartoon, not safe for work.
http://www.theonion.com/articles/no-one-murdered-because-of-...