We've hit up the local PR for some answers, but understandably it's not in control of the pricing or title listings for Australian Steam users. Our request has however been forwarded to those in the know, and we hope to have a reply for you guys later today or tomorrow.
In the past, Activision blamed Steam for similar shenanigans, and THQ was unwilling to comment on its activities. Maybe 2K Games will step up to the plate and be straight with us.
2K too good for Australia now!? [Steam Powered forums, thanks Cam]