This happens because the creators of that tool set their regional pricing for lets say... Russia at a much lower rate than other regions and did not region lock the steam keys!
This means the keys can then be re-sold to users not in Russia for example for lower prices. This is all legitimate there is nothing that restricts steam keys being resold and many sites offer this in many different formats such as the bundle site you linked.
The Steam process with TGC is still in the early stages so I doubt anyone will be able to comment directly on this situation just yet, but I am sure it will come up at launch time. We are working closely with Steam for FPSC Reloaded so issues like this will be dealt with hopefully in a way that is beneficial for all involved.
Windows 7 Pro, Intel i7 3.8 GHz (Passmark: 9021), 16GB DDR3, NVIDIA GTX 780 4GB Superclocked (Passmark: 8056)