I haven't had the time to read anything but the first page of this thread so please excuse me if I am repeating what others have said.
I am not a fan of Halloween. However, if it consisted of cobwebs, pumpkins, witches with broomsticks and pointy hats, apple bobbing, ghost stories - that type of thing - I would not find it offensive.
In its current form, I think it is absolutely vile. Over recent years I have seen an escalation in the sheer brutality of the occasion - a window with the silhouette of a man brandishing a long knife and a women cowering in front of him. I have seen lifelike looking dismembered, bloodied hands, terribly disfigured faces, etc. etc. etc.
In my opinion, this is a celebration of the very depths of human behaviour and personal tragedy and I think it is despicable to use this as entertainment for children.
But really it's all about money - the ghastly tat in the supermarkets, the selling of party food, costumes and the like. Any opportunity to big up the event and make more money.