ROFL. I was raised in a very large So. Baptist church in Oklahoma. When I was a kid we had Halloween parties at church and even had haunted houses put on by the youth. Something must have happened toward the end of the 70s to make the Baptists go PC or something. They are "all" against celebrating Halloween or something. Now most don't have a problem with participating but definitely don't want to celebrate it at church. That part I can understand. It's those that don't celebrate it at all that I can't figure out especially knowing how it was done back when I was a kid.
It is the Halloween which is evolving.
At first it was a pagan holiday of Samhain and it was not so good.
Then the Church established the holiday devoted to All Saints ( Halloween - All Hallows) and in Western Europe (where Samhain was popular) it helped to keep people away from pagan and magic practices. This was very good.
Then the pagan elements from Samhain started to seep into the Christian Halloween, and this was getting worse.
Than in the last decades, satanists, militant homosexuals and other corrupt movements started to make Halloween their holiday. This is very bad. I guess it is the time when many Christians in America started to see the problem.
Well, it could be a rise in the nuts that actually take Halloween as a religious holiday. Was New Age/Wicca (among other things) really around when you were a kid? While as it currently is, its modern form is mostly just a religion which appears made up to annoy parents, many adherents do celebrate Halloween as a religious event. Given that change in context, one should expect a change in attitude.