I don't think Itch really takes ratings into consideration. You can't even see the games actual rating. I think it's only used to help itch choose what makes it to the homepage. So unless you think your game is homepage worthy, don't worry about ratings
Viewing post in Rating a game without playing
I think that as long as the developer has at least the right to reply back or report such cases, it shouldn't be a problem. Or something to disencourage someone to just go on a mass spree of 1 star reviewing soccer games just because he doesn't like soccer.
Well, anarchy is fine too, playstore is like this. I just wanted to know if that was really possible and if there was really no way to appeal against such cases.