If we were talking school textbooks, which main purpose (presumably) is education, then this type of practice would certainly be inexcusable (skepticism for public schooling notwithstanding).
But in an arena where marketing and "target demographics" reign supreme, liberties are taken to maximize profit. Only shady thing here is the peasant & criminal roles going to blacks, I suppose the actors were probably desperate enough to accept them, and the producers wanted to "diversify" the cast with only menial roles, a shame but still a side effect of the business side of filmmaking.
Now asking WHY an all white cast is more profitable is a much better question IMO
Yes i understand that Film companies are looking to bring in the most money off of these films but even then that is not SOLELY the reason behind them blatantly showcasing a certain view of history in every single hollywood film.
Yes, that is the sole reason.
There's no movie producer who's mission is to restore the glory of the Aryan race through repainting history.
They're going with what the culture wants. And the culture is overwhelmingly white, and relates to white, and wants to see white.
Just like all the paintings of White Jesus. If I'm an Italian duke or king or whatever, I'm gonna want to see a Jesus that looks like me.