Same, I can understand wanting to keep certain things clearly secular to avoid mixed priorities. Still, retroactively going back to remove direct refences to things based on religion is needlessly complicating; especially considering that it is not being completed adopted by different groups. Christianity has had an undeniably major part in how western civilization has developed, trying to deny that is disingenuous at best.
It is one thing if it was changing something relevant, helpful, or necessary but it isn't. The adoption of the Gregorian calendar from the Julian calendar was to address a legitimate problem in how dates were recorded causing a growing drift in how the days were counted and their actual time of year. It was necessary.
This? Changing it from A.D. for Anno Domini (meaning year of our Lord) to C.E. for Common Era doesn't have a benefit. What does it accomplish? It adds confusion for some and makes others mad. I know it is reductive to say, but the motivation feels like, "Religion no longer exists. It has no place or effect in current society. It has never had an effect and will never be relevant. Having any mention of it taints the purity of our conventions of pure reason and logic." That's probably more than a little hyperbolic, but the point behind it is still there.