There's a fairly rational psychological explanation to it. When people cannot achieve a certain goal for a while, they convince themselves that the goal is not worth it, or tainted in some way.

Christmas has been traditionally associated with family, kids, happiness, seeing retired grandparents, etc. All these things have been sliding out of reach for the middle class with no reversal in sight. So this creates tension against people that can still afford it, and a perception that these goals are unfair and should not be pursued.

This is to be expected - it's not like the journalists writing the politically correct articles, HR people defining acceptable language, or moderators deciding on what gets approved are paid enough to afford what used to be a regular middle-class life 2 decades ago. So they rebel against it by trying to stigmatize it in the way they can.

And it's not like you can blame them either - the human brain is very adaptive at picking goals and means. If you take personal prosperity through hard work out of question, people will find other goals to pursue, it's just they will be much more divisive...