The US does not “ban” nudity, it puts a stricter level to it. IE, having nidity in US on certain consoles would move the rating to AO. And funny how you criticise the very same rating system to identify the game for adults (rated M for adults) in your critique.
The console maker beam counters are the ones who push for lower ratings to reach larger consumer base. Same with movies. R rated movies typically do less box office than PG-13. It is not a moral decision, but a monetary decision.