My problem with your argument was that you just tried to say that there is no place for such content, that it is distasteful, and so on, instead of "Yeah, this content limits my possibilities to play". It was hard to understand, what is the main problem for you? And this is not only about you. Other people also used this argument, but it does not look valid, because of how much content is done with M rating and is not supposed to be played with children or be viewed by them. This does not make the content objectively bad, just not content that suits them. "What am I supposed to tell my niece when she walks in while I'm trying to play?" vs "I usually have underaged people with me when playing, so including a filter or off switch would be useful for me" - same meaning, but less aggressive and shows what you are implying much better, I think.
As for BG1, 2, and 3 go together - yeah, I do not get it. But I would genuinely love to hear your explanation, no joking.
