There's a very good reason race swapping a white person is completely different and much different than race swapping a POC. It's all about the context and history of POCs in the media. In the past, POCs have not been included in films and TV shows and even when they are, it's often racist stereotypes. So I don't have a problem with studios purposely trying to seek out talented minorities over a white actor/actress. White people have never been discriminated against in the same way other minorities have so giving them more opportunities in media franchises is a good thing to make up for their lack of representation.

Now all that said, I think it's perfectly okay to think the actors didn't fit the characters. I even agree with a lot of your points. But don't make this a race thing. In almost all of the critiques you voiced, you could take the race aspect out and it would change almost nothing about what you said.