Valve's store, Valve has the say on what goes and doesn't go there.
That being said, I don't think Steam needs to be filled with asset flipping trash, but I also don't think it needs to be filled with the game described in the article either.
The dev has other outlets to go to, maybe they should try GoG and see how they respond (I imagine if they didn't respond in kind, you'd be quick to post about that too).
Steam is still a great platform for developers. Just because you want every single nsfw/slightly nsfw game under the sun to appear on their store, doesn't mean it has to. You don't even buy from Steam, let alone game on PC anymore, and yet you're always one to quickly post negative news when it comes to that platform.
Your rant would be much more believable, if this game wasn't Safe for work. Rated 0. Nothing sexual at all.