If the BBC referred to (say) Illinois as “State 32”, I think people would complain.
Even though these two things are equivalent, one is a name and the other is simply a marker.
So it is with BC/AD and BCE/CE. One states the truth that Christ has split history in two, whereas the other form is just a soulless temporal marker.
OK, some FReepers do not believe in Christ - but the Pope does. So he’s obviously right to fight for BC/AD.
Hope this was helpful.
Might as well not say “St. Louis” or “San Francisco”.
B.C. and A.D. are nomenclature of Western Civilization which is rooted in Christianity.