Steam reviews are maybe a notch above metacritic reviews in the scale of stuff that's totally useless to consumers.
The game has a decently big following for a new indie project right now, and because of Kickstarter any sales after it releases will be profit for them.
Because people are interested in it, streamers will probably pick up on it. Heck, the toybox has been a pretty prominent stream game for basically being nothing. Then, if the game is good it's only a matter of time before the steam reviews even out.
Also, they can absolutely delete steam reviews, and are well within their rights if a review is irrelevant or just incorrect. And judging by how quickly the discourse here has descended into people shouting "SJW!!!!!!!" and more insanely, "white genocide," I'm sure there will be PLENTY of irrelevant and incorrect floating around that review section.