Looking at you, streamers and angry defenders of Japanese ‘fanservice’ games.
If I were playing by myself and saw a random cock dangling on my screen, I would have a reaction and feel flustered.
You’re missing something big: it’s NOT a surprise. Literally the first thing that happens when you open the game for the first time is it asks you if you want to enable nudity. You have to answer that question before you even get to the main menu.
“Show Nudity” is still very vague. For any other videogame, it’d mean at best some nipples. The instance of full frontal in any media is extremely rare, hence the reactions are still justified. It would be a surprise, yes.