A week before launch. Fucking hell.

Steam's explanation is below.

I suspect the game was just too gorey. Note that the game isn't out yet, and I saw no indication that the authors of the article had played or seen it.

After review, we will not be able to ship your game HORSES on Steam. While we strive to ship most titles submitted to us, we found that this title features themes, imagery, or descriptions that we won’t distribute. Regardless of a developer’s intentions with their product, we will not distribute content that appears, in our judgment, to depict sexual conduct involving a minor. While every product submitted is unique, if your product features this representation—even in a subtle way that could be defined as a ‘grey area’—it will be rejected by Steam. For instance, setting your game in a high school but declaring your characters are of legal age would fall into that category and be banned. This app has been banned and cannot be reused. Re-submissions of this app, even with modifications, will not be accepted.

"Nobody wants to invest in a game that can't come out on Steam."

Speak for yourself. Valve and Steam becoming more and more frustrating to deal with for both developers and users, not that it was never not frustrating, but yeah, we should all move to gog or itch.io instead.

It's like monopolies are not good, actually.