On the coasts it is generally not safe to assume that anybody you run into celebrates Christmas no matter what they look like, and everyone's money is the same shade of green, so it's generally thought to be good form for businesses to put some effort into not offending anyone. Especially if that business has a multicultural customer base. That would work fine until somebody gets annoyed at hearing Happy Holidays from some store clerk instead of Merry Christmas. I have no idea how or why that should be annoying, but all that does is just add to everyone's headaches. In general the easiest way to get through life is to cut people a little slack and don't let anyone else give you reason to think you should be outraged about things like that.