The war z is a scam, to put it bluntly. This game is a money grabbing piece of garbage that was spit out by a bunch of cons. A game being a money grab is not a problem, as long as you're not misleading customers and pulling sketchy moves to make people buy it. It also would porbably shock you to know that the dev-team blatenly lied about several things also.
First of all, this game is a total rip off of dayz. I am not a DayZ player so there is no bias here but this game is a complete rip off of it. They took the awesome concept of dayz and just added a micro transaction store to it to pull even more money out of it. DayZ is a much better game over all and it's free, just buy arma2 on steam (Which goes on sale often)
Secondly, just take a look at this interview with a developer about the lies they posted about their game on steam. If that does not make you hate their guts, I don't know what will. Actually I do. Take a look at this post by an ex-moderater spilling the beans on their little scam they have running.
Lastly, valve is one of the best, if not the best, companies in gaming. Their reputation for a free gaming platform with no BS is great (Steam) Putting this garbage on steam is ruining reputation, it's saying "hey you can completely lie and post garbage on our reputable platform and get away with it" I personally lost a lot of respect for them over this, it's like selling a rotten tomato with knowledge of it prior to the sale and not doing anything about it. Just take a look at the discussions about the WarZ on steam, the customers are not happy.
In conclusion, do we really want a game like this on steam? and does valve want to have a game like this on steam? The devs are cons, they can play their little scam all they want but don't shit where you eat.