AD is from the first "Year of our Lord" if I was a Muslim then I'd be more offended by the idea that this was a "common" marker that I'm supposed to follow.

Other religions have their own callenders and the only reason we use the Christian one is because Christian powers have been on top for the last few hundred years.

We had enough trouble trying to get everyone to adopt the Gregorian calender for crying out loud, just because it was Catholic.