Wasn't saying Halloween had anything to do with the sun & seasons.
Was merely illustrating how competing religious beliefs interact & try to claim a holiday already established in a culture. It's a present day example Americans are currently experiencing. Children of Christian parents who object to halloween are disappointed when they don't get to participate, so you see churches doing a sanctified version where the kids still get costumes & candy.
Yes, American phenomenon, US & Canada, but Mexico goes its own way.