They cast Hamilton (Lin Manuel Miranda, a brown man, created the play and made the casting rules) that way because it turns the history of, yes, founding fathers but also, slave holders on its head. And using hip-hop and R&B, culturally tied to black and brown communities, to further cement the divide between the US and King George who uses classic musical music. The intent is to say that the US is as much our country as the Founding Fathers.
And, again, the Asgardians are aliens. They can look however they want as they're obviously modeled after Not Norse gods. They don't even SPEAK Norse in their daily lives. They talk more like Shakespeare, at least in the first and, partially, second films. And all the shot callers at Marvel are white ... You can't blame any other race for that. WHITE people decided that Heimdall and the rest of the Asgardians were like the human rainbow and not homogeneous like the Skrulls.
You can't seem to get that and your constant pushback is ... Weird.
I would, however, BALK at a black Aragorn or Asian or Indigenous Gandalf as LOTR is meant to be an olde British legend as he felt England lacked one (I don't think he considered King Arthur or Robin Hood old enough). And the Kingdom of Rohan were obviously modeled after Norse history. And that's how it should stay.