I grew up in a VERY conservative Baptist Church; half of the members didn’t have TV’s, no dancing, make-up was frowned upon...you get the idea.
The youth group designed and hosted a truly fantastic haunted house each year...blood, gore, skeletons, coffins, you name it. The teenage boys had a blast scaring the tar out of everyone!
I think Halloween, like Carnival, was orginally tolerated by The Church as a safety valve. You know, the more you (re)press, the more the pressure, so something’s gotta give.
I should say that to my grandchildren of preschool age, it seems to function as a recognition of the scary things in life, as personified by spiders and pumpkins. Great stuff ... well, plus the candy!