Valve does 'some' level of quality control, accordingly. But it doesn't involve completely rejecting a product from their platform. Rather, the game has a significantly less chance of being 'suggested' to people.
Which seems to not be wrong. When scrolling down the store or going through my queue, all these shovelware and asset flip games haven't been popping up there. But I used to be someone who preferred browsing "new releases". That section of the store is completely ruined. With the inability to filter out tags, nor apply our own tags (yet they're still called user tags for some reason), there's just waves and waves of visual novels, asset flip FPS games, early access bullstuff, and RPG maker games. On top of that, there's only a way to filter out non-VR games, but no way to filter out VR-only games.