Yeah, Steam, where the official western release was done. As for other sites besides F95 and the Steam forums, I wouldn't know, this is my source for the game and the Steam forum is the official forum for the game for western players, so those are the only two I pay any attention to. I have no reason to pay attention to PAtreon, nothing comes from there that I use in the game, not even the translation.
As for Steam allowing smut games, yeah, on paper they are supposed to be and they do allow the game. However, allowing the game comes with the condition that ANY AND ALL adult content is removed. They don't care if there is a patch to restore the content as long as the game on their service doesn't have it, but it still takes away from the developer's time and vision.