Casting an aryan actor to play an aryan is not racebending. Historical fact: In 1935, the Shah changed the international name of his country from Persia to Iran to stress the fact that Persians are aryans. Google "Hitler Iran" for more facts and mad theories.
However, boycotting a movie because it's directed by Jerry Bruckheimer does make sense to me.
But I'm tempted to see this one, because I love middle-eastern fantasies and the writers apparently take a few pokes at Bush and Cheney.