One thing I noticed while reading the whole thread: Americans are really hung up about sex and nudity.
So, letting for example your child play the evil playthrough where part of the campaign is murdering whole families is fine, but the dealbreaker is the reward sex from the evil drow cleric. And other gamers wanting any content that offends them (in this case sexual content) to be opt-in only so that they can avoid it where possible, in a game that deals with a lot of very dark storylines and concepts (like torture, murder, slavery, BDSM etc) is a very odd concept (for me).
I understand that these players want a very specific type of game catering to their specific taste, and that as such is fine, I just have the feeling that this is not the game for them. There are games out there that I DID not play for similar reasons, such as Rust, but I never expected the devs of Rust to change the vision for their game to cater to my sensitivities.