The Celebrating of Halloween is to give the energy--power and sustenance to the Energy behind Hallow's Eve. which is Satanic in nature. It's the sacrificing of children: young virgin girls primarily--kids--in order to utilize their life force to propel dark, anti-human agendas. What those agendas entail is another topic entirely. For now, let's look at this one aspect.
When we participate in these 'celebrations' we are energetically supporting these dark action plans. It's not intentional in most cases, but it is a reality all the same. It's like math. Magic, Spell Casting doesn't care that you have an innocuous view of what you are doing and it can be used for good or ill, regardless of a lack of awareness.
Many people are like, "C'mon now! I am just having fun and enjoying the Holiday--which means 'Holy Day'--in my own way. I'm not satanic and I am not intending to support any dark agenda." Ok, I say. Well, do YOU think it makes sense that you can 'celebrate' the Holy Day WITHOUT adding your energetics to the Structure? I don't think so. Sit with it. Meditate with it. Come to your own conclusion and keep in mind that you live again and again. Where do you want to attribute YOUR ENERGY? How do you want your Soul energy to be utilized? Do you want carry that forward? Do you want that to be part of your energetic signature? Feel it. Do you want to support that energy?
The actual Satanic Ceremonies that are part of the Origin of Hallow's Eve. are taking place in covens around the world every year on this day while Humanity is Celebrating the Day and lending their energy to help power the real ceremonies that are going on, totally and completely unbeknownst to them. It doesn't matter that Humanity, at large, is unaware of this. The Mechanics of Energy are the same.