There is one company here in Argentina who is selling a game through Steam. It's a rather bad game (so no "good games only" filter I guess) from what I've read sadly BUT they have it there, and no other company involved besides Valve of course.
If you are talking about War Z, I think that media frenzy was majorly overblown. My brother bought the game (knowing it was in early alpha), and it actually looked fairly fun (coming from someone who usually is very bored with the typical online game and almost all zombie games). He didn't regret his purchase. It was fun enough that I enjoyed watching him play the game and considered playing it myself (but didn't for a lack of time).
The developers, being heavily inexperienced, made a number of honest mistakes (like copy+pasting their Steam greenlight description of desired eventual features onto the Steam game description and forgetting to mention it was in alpha because it was already common knowledge and already had media attention)
The game was very well received when it was in private alpha. Greenlit by the community, Valve approved it. When the game launched in open alpha on Steam, all the people who bought the game without understanding what it was, instantly created an uproar, got media attention, and the media devoured the game developers, and Valve pulled the game from Steam.
Right now it's almost midnight. Here are the stats for the War Z official forums:
There are currently 985 users online. 438 members and 547 guests
Threads 23,009 Posts 421,875 Members 230,211 Active Members 95,045
95,045 people currently don't think it was a scam, even after the media fallout. The 20k+ private alpha users didn't think it was a scam. My brother and I don't think it's a scam. The good critical reviews of the private alpha didn't think it was a scam [1][2][3]. Only the hoards of uneducated Steam greenlight users who didn't do their research thought it was a scam. War Z is no longer sold on Steam, but Valve re-activated the game for people who already bought it, and lets the developers give new steam keys to people that currently buy the game off of the developer's website.
Valve: "From time to time a mistake can be made and one was made by prematurely issuing a copy of War Z for sale via Steam [after our community told us they wanted it released in its current state by voting on Steam Greenlight]. We apologize for this and have temporary removed the sale offering of the title until we have time to work with the developer and have confidence in a new build. [That is to say, until enough time has passed so the steam community forgets about it and the developer can at least get the game to a 'Beta' state instead of alpha]" Red ink is my addition/interpretation.
The greenlight system is flawed, simply because most of the users seem exactly like the immature and unintelligent hoards of users found elsewhere on the internet (read the Steam greenlight comments for 'Pending' games. "Does the game have zombies? Is it a Minecraft clone? Is this singleplayer game an MMO? No? Then I wont vote for it!"). I honestly feel bad that this otherwise off-to-a-great-start alpha game now has a 18 metacritic score and no longer purchasable on Steam because Steam greenlight users don't understand what Steam greenlight even is, and because the media likes to over-exaggerate things to get ad impressions.