I am not angry, but seeing people complain for no legitimate reason, or whining about how something isn’t perfect for them, so it must be horrible business practices or Disney being out to get people is absurd.
Unless this was your first ever Disney trip, you would know had opportunity to know that Disney does the Xmas parties every year. This isn’t a surprise, but you still chose to go anyway.
You have kids and a job, so do almost everyone else that attends Disney. I find it extremely non-credible that out of 52 weeks in the year, the only one that fits into the school/work schedule for a vacation is the one single 7 day period that happens to have the most Xmas parties.
As to costs the point that the Xmas parties are so popular and sell out so quickly and completely is objectively evidence that the costs are NOT to high and that it continues year over year that people continue to see value in it. If you personally subjectively don’t like them, that’s fine, it’s your opinion. But it’s not a failing or fault of WDW to keep offering things that people like, at a cost people are willing to pay.