Why are the ancient Egyptians culturally misrepresented in cinema?

For the longest time I have had a bit of a problem with Hollywood consistently casting White actors to play ancient Egyptians. Examples include Cleopatra, The Ten Commandments, Manequins I and II, and the Mummy Movies (thankfully not the Scorpion King movies). I mean Egypt is a country located on the African landm as such most people native to that continent are fairly dark skinned. So why does Hollywood have such a problem with this?