That's just what some publishers on Steam would like to have you believe at least. It seems as though only North America is receiving a number of the new titles appearing on Steam, and the rest of the world is just none too happy about it. The group, Rest of World (ROW) on the Steam Community, is trying to show publishers the sales they're missing out on by not opening their titles to other territories.
Michiel Verheijdt of Ubisoft Netherlands told that the choice is purely economical. "In North America Steam is used a lot more, there are more online sales there and offering the games on Steam isn’t free so Ubisoft chose to only target that market". Verheijdt also mentioned that there are plans to expand the offering. The publisher is currently investigating how to do this (this does not necessarily mean on Steam - Kapitein Iglo).That was part of a response given to the group. Feel free to show your support for them by joining up with some calm, like-minded individuals.