I could support adding Yom Kippur if I were French, but taking away Christmas and Easter (Passover) to do so would be wrong, and certainly not add El Cid!
“....and certainly not add El Cid!”
I think the name of the Muslin holiday is “el Aeid” or something close to that.
el Cid (Rodrigo Diaz) is a Spanish medieval hero who helped banish the Moors from the Iberian peninsula. Maybe the Christian nations should have a holiday named after el Cid? We could name it as though it was for the Muslims, and then the Christians could celebrate el Cid instead. We could pretend to be ignorant and celebrate el Cid.
That's a bit blunt...