It's not a penis envy (there's no reason to envy a guy with half a meter dick, we can only feel sorry for him). If you don't care what you see on the screen then why bother playing at all? I don't see people complaing about the size of fairies or wondering why Olivia's mother is twice the size her "coworkers", or wondering why all body fluids are completely unnatural. It's not beacause it's fantasy game with magic and fairies. There's "error limit", everyone has his own. Every inconsistency (with real world of course) sank on that limit and when it's full things like unnatural dicks becomes real bother, something that breaks immersion, messing with the pleasure you have when playing this game. Our mind can endure many things but when things mind have to endure are bigger than pleasure from the game it's becoming uncomfortable.
Anyway, there's no reason for MC to have unnatural dick, it's just dev's own issue. Just like big boobs. There's boobs of each size (especially with patch), but the thing is game leads you to sex scenes with women with unnaturally big boobs. And I still don't see a choice to refuse those boobs. There's some people you cannot evade to have sex with. Like your moms (step and biological) and after this update it seems that every woman older than MC (by appearance) will have sex with him without player's consent. Even with futa, you can skip a scene but it's clear that you two had sex. Those "story rails" are really annoying.
I personally can endure giant dick, it's near my threshold, I just think how bad dev at rendering and go on. What really kills all the pleasure for me is renders for supporters inside the game. It seems logical to me to put such renders in some sort of gallery, like galleries in other such games, but when you put it inside your game, just like story screen then picture for supporter then next story screen it just kills the game.