Steam and iOS are also walled gardens with strict DRM where the games have to tightly integrated into the platform to be accepted at all. And someone could own a game from elsewhere, or have downloaded a free copy from a key or promo. There's still no way to know for sure.
Viewing post in Rating a game without playing
Seems like my question is answered. The answer is: "Yes, you can". You just have to agree with it to post your game here, like the playstore. Still feels bitter not being abble to answer a review even when people bash you just by looking at your game's screenshots, because they feel like (just like the playstore).