As far as I know, the other publishers (ie. Activision, THQ, Paradox etc.) have the final say as to when and where their games are available on Impulse. I don't know any more than you do about how much pressure Stardock applies to get certain titles available in certain regions.
Besides, it's preposterous to assume that Stardock hates all of Europe. Maybe they hate a certain country, like Luxembourg (who likes them?
), but to hate an entire continent? That's taking it a bit too far...