There is also how some players try to immerse and identify with the protagonist.
The protagonist having vastly different core qualities can make that difficult. Sure, the protagonist does things, that no normal person would ever do. Like fighting dragons, doing magic or generally be the hero of a tale. That leaves the mundane everyday life things to relate to the hero. Like having love interests. Or a sexuality.
So it is a tricky thing to include lgbt elements. Attach it to the main character and risk estranging that character from the majority of potential players. Attach it to a side character to just have it for the sake of having such sub plots? Making the story centered on those elements or having them just appear?
Would gay Mario trying to find his gay platonic prince friend in another castle be a distraction or an incentive to play the game? I go with distraction. Trying to rescue the princess is just about one of the oldest hero tale tropes. It is not relevant, but only serves as an alibi motivation. Any other reason would have done the trick.