I'm a former Muslim. I'm not offended by the OP's action, I just think it's a dumb joke that shows a lack of sensibility and respect.
The key is, in the West, if you did what I described above, you would probably receive a lot of flack, but you definitely wouldn't go to jail!
Was in it poor taste? Sure. But no one went to jail for it, no one was at all punished for it, no one really cared. So when the person I responded to decided to admonish these people for doing something "offensive to muslims and non muslims"... well for one that's objectively false, and for two that's ridiculously backwards from the culture of tolerance that I was raised in. His comment was more offensive to me than the action these folks took by several orders of magnitude.
It's impossible for me to fathom any serious repercussions stemming from offending the sensibilities of religious people. Because where I come from, that's basically a national pastime.
Of course, what makes it really difficult to compare is the huge difference in attitudes towards and the role of religion between the cultures.