This is the real reason secularists hate the terms, with the cover story that it is offensive to Jews and others who may not believe in Christ. Most practicing Jews I know are OK with it. Secular Jews, not so much.
So you wish to appease Secular Jews who vote 90% Communist Democrat. That does not take the culture back from the collectivists.
The modern era is highlighted by discoveries of metals and their processing. Metal raised us out of poverty. It is the periodic table of elements.
Christ occurred at the same time as metals processing.
Metals are not an event.
Christ is an event.
You heard it here first folks.
That is the secular explanation why Christ is the event, and not Moses or a supernova.
But doubly, Christ ushered an era of liberty, and hence progress.
You will not get that explanation at the University College of State Collectivists because Academics are conformists not scientists.
Take your culture back. Now. :-)