My work here is done.
Pumpkin pie is associated strongly with US Thanksgiving, and to a lesser extent, Christmas.Me? As a food, I love it. I use it year-round in every recipe that calls for cinnamon: oatmeal cookies, cinnamon rolls, you name it. Years ago I was baking an apple pie but discovered too late that I didn't have any cinnamon...I used pumpkin pie spice instead, and now I can never go back.
As a cultural phenomenon, I'm....confused, mostly. I mean, it's a tasty and aromatic spice blend, but it's just one of several in my pantry. (Why no love for curry spice or chili powder?) But I'm not gonna hate on someone else's good time: life is short, let folks enjoy stuff.