This kind of sentiment gets pushback because it is SUCH a personal preference. I wouldn't have even picked up this game if the MC had been their own character with their own appearance. It's extremely common for this gray hairless androgynous-looking character to be a stand-in for YOU or YOUR UNIQUE CHARACTER in these VNs. You can fill in the blanks with your own imagination. It's meant to be "unfinished"...because you finish it in your mind.
I've had a pretty unique life (as have most people) and I know I'll never see someone like me represented, unless I tell my own story. I have no desire to do that. I just want to yume with some fun characters.
In this game, the whole point is that the love interest will fall for the MC because of their actions, no matter their appearance, so it makes even more sense than usual to have their appearance be a blank slate. It's not the kind of story you may want to read or tell, but I wholeheartedly disagree that that makes it a lesser story than if it had had a MC with a specific appearance.
And I'm pretty confused why you feel so strongly about this, as I haven't heard anything about the creator being forced to make a self-insert MC or anything. If you ever make your own VN with an OC MC, I promise I will read it! But your preference is just that; a preference.