Is there a reason in particular this needed an all white cast?

Fairy tale characters are usually portrayed as white because their origins are usually German or Swedish. Also, the actors in the original musical were white.




Can't pin me down
When you play the game of thrones, you win or you die.

There were dark-skinned people at the wedding.

I like to think I'm always right :-) 

These are all medieval european fairy tales, and these characters as such, can only ever be white. Making any one of them some other race would be racist.

___
Anyone who has ever read any spoilers,
knows that Winter Is Coming

Since the plot was based on white people's folk tales, this was one film that really does call for an all-white cast.

However, it does not call for a half-Brit-half-American cast, who make no effort to sound like they're from the same region. I mean, a witch with an American accent lives next door to a British baker and his wife? That really becomes grating, if you watch the film more than once.



“Seventy-seven courses and a regicide, never a wedding like it!