Sadly religion has a lot to answer for and is the reason for many conflicts we now see around the world (and in the past).
For my immediate, family who have been brought up as anti-theist's, we don't celebrate Halloween, but we have (and still do) participated over the years my children have grown up, simply because it brings family and friends together for a fun packed evening. My children are now at university, but we still deck out the porch and windows facing the public with Halloween paraphernalia as we think despite its dark undertones, it's just a fun night; once its over, everything returns to normal. Unlike the Christian celebration, which takes hold months before the actual event. We even have a TV channel that airs Christmas themed films 24/7 from late September until Christmas is over. We tire of it very quickly these days, but still celebrate it as a family occasion and participate in the commercial thing, spending lot's of hard earned cash on gifts and overindulgence's etc. Again not because of any religious connotations, but just for the sheer pleasure of buying gifts for family and friends and the companionship of family away from work for a break.
I was originally brought up as a Methodist and attended Sunday school as a child (I still have the Sunday School stamps we earned for attending). My mother used to be one of the Sunday school teachers and, until my early teens used to attend church, every Sunday, attended various religious events such as walking days and carol singing (where the money we were given was used for repairs to the church) and was a member of our churches choir for many years.
I was an avid reader from a young age, partly because I lived with my grandparents for a significant portion of my childhood due to my mother being ill and my father working away from home. . My Grandfather was a hard working caretaker at a local school and every weekend and school holidays he would spend most of the time stripping and rewaxing the parquet flooring that was present throughout the school. I was allowed access to the library, where I would virtually the whole day, every weekend and school holidays pouring over non fiction books that fascinated me.
I soon realised what religion had done to the populations of the world, so left religion behind gladly and have never looked back. Don''t get me wrong, I have always respected the feelings of those who still believe there is an all powerful being that knows everything, and usually don't preach my beliefs, but I won't be conned into believing there is a god, who, from all the literature comes over as a cruel, selfish, false, harmful, and authoritarian being, that would be better shelved with fictional books, in the science fiction categories.
Watch some Christopher Hitchens debates on You Tube. He regarded all religions as dangerous and cruel. You won't find any debates where well respected religious leaders could get one over on his reasoned arguments and all fell beneath his amazing knowledge of religion. It was a sad loss to the anti-theist's movement when his overindulgence's with alcohol and heavy smoking saw him leave this world several years ago becasue of cancer.
The attitude of the charity shop volunteer is in my opinion despicable. The whole point of a charity shop is to sell 'usually second hand' items so that the proceeds can be used for good. As someone pointed out earlier, Halloween has become very commercialized over the years since I was a kid back in the sixties, so there's a a lot of second hand merchandise that potentially could be put to good use by recycling it via charity shops. Also its one of the many things that contribute to sound environmental practices by recycling the goods instead of dumping them in landfill sites that blight the landscape.
There's no afterlife, just nothingness, so go enjoy the short life you have to the full and leave behind happy memories for your surviving family.