Steam now has a feature that lets you manually hide games you own on other platforms
If you play a lot of games, there's a good chance you own multiple different platforms, and have an extensive library of titles across your systems. The biggest PC storefront, Steam, seems to understand this, as they've just updated their store pages with a new feature that allows players to mark games as already owned on other platforms. Now, you can stop seeing constant advertisements or recommendations on Steam's home page for games you've already purchased and played on consoles, without putting the game in your ignore list. All you need to do for this is visit any game page on Steam, hover over the ignore tab, and check "played on another platform". Doing this will remove the specified game from your recommendations, but will use it to recommend you other, similar games you might not have tried yet.
Source
The data EGS stole didn't just contain games you owned, but your friend's list on Steam, what you played last, how long you played XYZ etc etc. 
