It's a government subsidy just like any other. It's a huge one, and many carriers are complaining about it. They argue Emirates should be charged extra fees for their US service because of unfair competition. I think that argument has merit given US carriers have to pay market price plus taxes on their jet fuel.

Emirates gets huge subsidies because its a goal of Dubai to become a world air hub. It certainly makes sense for them given their geographical position but I don't see how US carriers are supposed to compete with that.