Do people actually get religious holidays off? I dunno, it wouldn't seem practical to award special days to people based on religion. What do Agnostics and Athiests get in compromise? Nothing?
That would create for a possibly hostile workplace...
Yes, as mentioned before, this has been the case for a LONG time. There are so many different Winter holidays though (Christmas, Hannukah, Kwanza, etc.) that schools are usually closed for weeks, and adults (though the actual days are just the Holiday off) will typically take perhaps a week off for the holiday. Easter is also recognized, but schools do not close for long unless it falls in the same time as Spring Break.
The fact is that so many people practise these Holidays and will take those days off regardless of whether the said day is recognized by the state that in the end you'd just have a work day in which 75% of your staff is absent. In that knowledge, it's better to close businesses and take a day off than to run the business on fumes and essentially put the market in the red.
Aethiests and agnostics do not practice such Holidays, and that's fine. But it also means that there is no day and no reason for them to celebrate in such a manner. They should just enjoy the swag of having the day off and not complain about religion, whether or not they likely consider it a "primitive, primevil and illogical" sort of thing, which often gives them their unreasonably prickly demeanor when they take issue with the majoritive religious.
And unless you're talking about aethiests, I see no reason for there to be hostility in the workplace due to religious holidays. Christians don't take issue with Hannukah, and the Jewish don't take issue with Christmas. We coexist peacefully and respectfully acknowledge each other. It just works.