"In other words, they are attempting to appease everyone--but in the game of political correctness"
Political correctness is doing what you otherwise wouldn't do in order to appease an 'offended' group.
Walmart decided to switch to "holiday" in order to attract the largest possible audience nationwide with their generic promotion.
In other words, they weren't "politically correct" in your favor in worrying about offending people like you who think they have to use 'christmas' instead of holidays.
Like it or not, you are the one who is trying to enforce your own brand of PC here. Walmart is doing what they want to best market their products, and you, of the offended class, are upset they didn't kowtow to your whims.
It's political correctness, just with a different side being the "correct" side. Deal with it.
But the largest single demographic for Walmart is Southern and rural.
Why is it good marketing to possibly alienate that demographic?
PC is also doing what you otherwise wouldn't do in order not to offend another group.
The PC crowd has no problems at all offending Christians--they revel in it.