Obviously, much of the merchandise that can be used to celebrate "holiday" can also be used to celebrate Christmas. As such, Christmas isn't a "second class" anything, but merely a logical subgroup.
So, then, if Christmas is a subgroup of the "generic" holiday, why is Kwanzaa and Hanukkah not also part of the generic "holiday"?
Give me a break. If Americans actually gave a crap about having friendly, respectful store clerks that wish you Merry Christmas and know your name and (dare I say it) care about what's important to you, the entire concept of Wal-Mart would've been an absolute no-go. Instead, we know the opposite to be true, as it is the most popular company on the planet!
I'm not saying it's good, I'm just point out reality. We traded friendly merchant faces wishing us Merry Christmas decades ago for butt-cheap prices...and did it gladly.