Why not cast white actors for white roles?
You can argue that most anime characters' ethnicity are not clearly stated, but in FMA there are clear racial distinction between characters. Characters like Edward, Alphonse, Winry, and Alex Louis Armstrong are clearly white characters while Ling Yao and his retainers are obviously chinese. This isn't even the case of anime character designs looking slightly Caucasian and having Japanese names, they are white characters with western names.
Raging Bull = Best movie