> I think a lot of the worst preachy PC behavior policing, like telling people it's insensitive to wish people a Merry Christmas, happens mostly online or in echo chambers.

For what is worth, the only places I've seen this entire "merry christmas" thing being a problem has been as a backlash against corporations trying to look more inclusive by saying happy holidays in a period where there are multiple holidays being celebrated by multiple religions, but might just be my own filter bubble.