It wasn't anno Domini, it was of the Common Era. Bullshit. Why do we use a Calendar where the months have an idiotically variable number of days? Why do we use a Calendar where half of the months are named after Pagan gods and the other half are named after numbers (that don't correspond to their ordinals)? Why do we use a Calendar that is neither absolute nor relative and crossing where Year 0 should be is a pain? Why do we use a Calendar with a Leap System accurate for only 4000 years? Why do we use a Calendar that has been moved several times over the course of the centuries? Why do we use a Calendar with 7-day weeks? Why do we use a Calendar whose origin is the (presumed) date of birth (or by some accounts conception) of the Christian God? Because it was divinely given to us by the Pope.
Replacing anno Domini with Common Era does nothing to change the Christian origin of the Calendar and serves only to perpetuate its (divine) "rightness". In its historical light, the use of "Common Era" can be seen as merely a shortening of "the common era of the Nativity of Our Lord" or "the common era of the birth of our Saviour". Ever since I got my very first checking account, I've been writing AD on my checks. Most people who notice it are bemused that I would put in the effort, but a few people, mostly Chinese and Jews, understand the point: The Christian Calendar is not the One True Calendar. Yes, it's the one used (nearly) everywhere right now, but not only could that change, but there are very good reasons to do so.
I've also, as an intellectual exercise, been keeping track of the date using the Calendar of the Illuminati that I devised back in 5999, after rereading The Illuminatus! Trilogy. If anyone's wondering, today is the second day of the month of A, 6007. For eight years, I've been telling time in my head using another Calendar, and it's been interesting. When we hit the next Leap Year (6011, for those of you who are counting), I'm planning on making some of the adjustments I've been thinking of, including adjusting the Leap System to remove some of its swing.
We haven't reached consensus on which Calendar to move to (I'm currently favoring the Tranquility Calendar with my Leap System), so I'm content at continuing to use the Christian Calendar. But I find it intellectually dishonest and disgustingly PC to call it anything but.