People who "don't celebrate Halloween" freak me out. In my universe, that's like saying "I don't celebrate Friday," or "I don't believe in gravity." Halloween happens, man. You don't get to choose whether or not there is a Halloween. The sky becomes dark. Crows grow their winter feathers, fresh and black, a color beyond the limits of our visual experience. Cold seeps into our bones. You don't have to dress up or carve a pumpkin--all of that dark, cold stuff is going to happen to you whether you like it or not. That dark, cold stuff is what Halloween is.
To deny Halloween is like denying winter and death and darkness. You can deny it as much as you like, but you will still be cold, winter will still kill your garden, the sun will set and you will die. Nothing can change that.
You don't have to party on Halloween, although it is a basic human instinct to make merry in the face of hardship, and to reject that instinct is often indicative of a sprained sense of fun. Many people keep the season in a somber, respectful tone. I suppose that's not truly celebrating Halloween. But it is honoring the day. It is surviving it. It is reflecting on the meaning of the moment.
Halloween is a time to look into the darkness of the world around us and take its measure. It is a time to think about fear, to embrace it, to make a joke of it. Halloween is a time to reach out to death and walk in its footsteps. To do these things enrichens our human perspective; doing them validates our choices that bring good into the world and strengthen our appreciation of the bright and the beautiful. We are lucky our culture has created a special day just for those activities. We are lucky that all around us, our fellow Americans are partaking in them, turning their gaze into the dim night and facing it readily.
On Halloween, the shapes in the darkness are just children with an appetite for sweets. Some of the costumes are scary. Some are cute. But if you don't look, you'll miss out on the good ones.