Lol, I mean it does sound trivial, but some people can be very... "passionate" when it comes to dick size of fictional characters, especially on R18 games marketed toward gay men. You can see other crowdfunded indie game projects targeting gay men almost always include dick size in their profile (some even go as far to put detailed info like girth and erect/flaccid size as fun trivia in fanbook, lol). In the end, games like this are built on players' fantasy, so no harm done indulging with people's fantasy, and build bigger fanbase that way.
Nobody said Draco can't have bigger penis ;)