How so? This is an LGBTQ+ visual novel. If you're talking about the two mums - It's not that unlikely, there are straight couples in this too.
If you're talking about the fact that we can change/pick pronouns, have scars etc. its so you can make the character feel more YOU.
If it's Cove's sexuality, it makes sense, he will be interested in the player no matter their gender identity and how it fluctuates throughout the game, the demisexual part I think comes into the fact that he knew them for + years (hi being 8 when the game started to him being 13 when you can start dating him)
The insclusivity for me didn't feel forced and made me feel extremely seen.