Maplewood NJ was one of the whitest, wealthiest, and most cosmopolitan suburbs in metro New York City in the 1960’s and 70’s.
As for Evangelical Christians, I spent much of my youth in the Deep South, and I recall only two families in my school that refused to celebrate Halloween, and one of them was the minister's family of a local Evangelical church.
I currently live near Seattle in a town that is 35% foreign born.
I can tell you that immigrants love Halloween!
I walked through our local upscale mall last night on my to the grocery store. Parents, and kids wearing costumes, were packed shoulder-to-shoulder inside. I have never seen anything like that! And, since most of them are Asians, everyone was polite and calm and respectful of everyone else's extremely limited space. Completely remarkable.
Secular Halloween’s gotten filthier since then, positively demonic in some cases, and I’m sure that has made backlash easier. But there’s long been a grumpy streak against traditional Christian feast days since the Reformation. It was only a couple hundred years ago when self-respecting Puritans wouldn’t be caught dead celebrating Christmas.
This is a war within as well as outside of Christianity where the pagans and the evangelicals happen to be on the same (wrong) side.
Halloween is All Hallows Eve = the Eve of All Saints day. It is not a pagan feast, and never was.