The Witcher and The Witcher 2 didn't have genitalia from either gender in it. The problem is one of biology. It's much easier to creatively conceal female genitalia in a scene than male genitalia and still make it look natural. Take the bath scene in The Witcher 2 for example. Triss was completely naked, but there was nothing showing between the legs. With Geralt, they got around concealing his junk by having his pants remain on. I don't for a second think it was because they were bigots. I think they understand that actually showing genitalia would be crossing a line for too many people, so the best they can do is show the chest and derriere.
It's no CDPR's fault that we view female and male breasts differently! lol
As for your accusation of people thinking "nudity makes it mature", I'd argue that the other side is just as guilty by saying "nudity makes it immature". The proper way to look at it is in context. Nudity can be either mature or immature in the right or wrong setting.
Well, just to clarify, I am not calling them bigots. And, to your last point, I made that exact same point as well. I think both sides are incorrect.
To your point about "genitalia and our views on nudity": Yes, female genitalia is internal and male is external. However, societal views on lower frontal nudity is similar for both males and females. So I see a fully nude woman (pubic hair visible) and a fully nude man (penis visible) to be comparable. Not the same, but comparable.
If CDPR wanted to have comparable nudity and not show any genitals, they could have shown Geralt naked (including pubic hair but no penis) since that's essentially what they showed with Triss. But instead, they kept his pants on. they didn't even show him rear from behind. If they wanted to be comparable and keep his pants one, then they would have kept her pants on too.