ph0b0s123 said:
So most are supposed to be Asian. But there is no way you are going to convince me that the two bothers Elric brothers from Fullmetal Alchemist with their blonde hair (yes, know lots of asian kids dye their hair) and blue eyes are Asian. No way.
Now I'm just being picky and someone might've already told you, but Edward and Alphonse don't look Japanese because they aren't supposed to be Japanese.
Their looks came from their father who came from a country that was wiped out a long time ago. And even if that wasn't the case, Amestris isn't based on Japan at all, but rather an alternate universe version of England (after WW1, if I recall). In fact, in that setting, I'm not sure an alternate Japan does exist; Xing appears to be mainly based on China.
So that's why you're not convinced they're Japanese. Because they aren't.
(Also me being super picky, but their eyes aren't blue. They're golden)
OT: Parroting what others have said, art style.
Also, characters with odd hair colors stick out and are easy to identify. That's why they're used as main characters often.