“Oh, what terrible a man I am. Giving kids stuff to smoke.” Robert smiled.
This is the line in question. Robert does "dabble" in Christianity. He is a war veteran. For the line to be realistic it doesn't mean all of society has to find smoking taboo. It just means that some people(ideally a vocal minority) would frown upon it, in order for it to make sense. Also, he kidnapped three boys, murdered one, and is saying this to the two still alive as a sarcastic joke, acknowledging how nonsensical his statement was.
Pretty much even if only devoutly religious people would frown upon an adult giving a 12 year old a cigar, I still think it makes sense for him to say such a thing given the circumstances. Based on the answers I've gotten I'm going to include the line, unless if someone has more dispute for it. Thank you.
I'm sorry for not having more details in the OP. New to this.