An example of a movie that gets hit for whitewashing that I think is wrong is Ghost in the Shell.
That stared Scarlett Johanson. Fans said that it should have been played by a Asian actress. But in the story, the Major (Scarlett's character) is a full body replacement cyborg. Her body is deliberately ethnically ambiguous.
In fact, the AI Puppetmaster has a body made that is identical to hers except the hair is blonde. The 2 bodies are identical, even down to the blue eyes. The only thing that is different is the head of hair.
So, within the story, there's not a specific reason for the Major to be played by anyone with a specific look. Anyone could be the Major.
The "butts in seats" casting is used a lot to justify whitewashing a character. Like Emma Stone being cast to play a character who is specifically a Native Hawaiian character. The character is specifically of Native Hawaiian ancestry as a part of the function of the story. It's a necessary part of the plot.
But they cast a white woman. Because she was popular. This should have been an actress of Hawaiian ancestry.
Barbie is another example of a specific look with the character. If you have a story about A Doll leaving The Doll World to the real world, that doll character can be played by anyone. But this is about a specific thing that was created at a specific time. Just like a Civil War era story in the south. Certain types of characters are going to look specific ways.
Wally West, on the other hand, there is nothing that requires Wally to be white. How does Wally get his powers? Same way Barry Allen did- he gets dosed in chemicals and struck by lightning. What about that requires a specific look? Nothing. Wally can be played by anyone.
Saying that because Wally is traditionally depicted as white as a reason to continue to only cast white actors is the racist part. There's nothing about Wally that requires him to be white, so you don't have to continually cast white dudes.
With this: "If race matters for characters one way - it matters for characters all ways. If it's only ok to replace white characters... that's racist." You're missing the point.
If there is not a specific reason within the character or story that requires a specific type of look, then anyone can play that role.
If you take Robin Hood. If that's a "true to history" telling, then that's going to be a white dude. Because in that time, late-12th-century with landed gentry England, that's going to be a white dude.
If you take Robin Hood and put him in a fantasy world of elves, dragons, and so on, anyone can be Robin. Because you've disconnected the requirements of late-12th-century England.
We've established that the majority of characters don't require specific ethnicity and the things you need to look for that are key elements that require a specific looking actor for specific roles but the OP asks why is it racist when white actors play a part that was traditionally played by a specific ethnicity actor?
That's because of under representation of actors of color.
The vast majority of roles are given to white dudes and then white women. And for no real reason. That's a hard fact of this world. So, when a role that has traditionally been played by actors of color goes to a white actor, that's not cool. People get upset because those actors of color are being excluded from the few roles they do get to play.
And the few roles actors of color do get are because of a key requirement. So, when that's taken away and the role is given to a white dude, it's upsetting.
Because, remember, it's really very few characters that require a specific skin color. And the best actor, regardless of skin color or ethnicity, should get the part. But the hard truth is that most of the time that "best actor" just also happens to be white.
So, yeah, it is racism when a white actor takes on a role that is usually/should be played by an actor of color.
Because if there's no real reason for most characters to be white then why are most characters played by white actors?
(Hint: it's systemic racism)
And if you're thinking "Well, whistlelock, aren't most people in hollywood liberals?" Yes. I think that's the case. I can be wrong, but I would bet the 'average' person working in the film industry would consider themselves liberal.
And if you're thinking, "well, doesn't that mean all those liberals are racccissssssst?"
Yep.
It does. It's called systemic racism for a reason.
Individually, those people would not describe themselves as racist. But they're still casting white actors over actors of color for no reason. Black male actors usually only get offered the part of gang members. Same with latin men. Indian American men get offered parts as long as they "do the accent."
Remember the Hector meme? actually, I'll add it. That's a perfect example of narrow roles being available to actors of color.
So, casting a white actor for a role that is traditionally played by an actor of color is usually result of unconscious racism and prejudices.
But let's look at another character: Ariel from The Little Mermaid.
What requirements does this character have?
1) Enjoy singing (it is a musical, afterall)
2) be infatuated with the surface world
3) be a fish/mer person.
After that, Ariel can be whatever you want. White, Latina, Asian, or Black. Ariel doesn't even have to be female. It can be a merman. You can swap out the Prince for a Princess and tell the same story. Or even keep the Prince a prince and it's just a gay couple telling the same story.
You're still telling the same love story. Change those 3 key elements alters the story considerable. Skin color of a mermaid doesn't change anything.
Nick Fury from the MCU is another character whose skin color doesn't change who they are. Nick just has to be 1) an American who is 2) the head of SHIELD. After that...Nick can be anything. Even female.
But what about the movie The Last Emperor? It's a story about the last Emperor of China. A key element of that story is that they're Chinese. So, this needs to be played by an Asian actor.
But if you say something like "but that character has always been portrayed as a white person," that's just garden variety racism.
The only time an actor needs specific appearance is when the character has key elements that require that appearance. The more fictionalized you make your story (disconnecting it from our real world) the less and less you need characters to look specific ways or have specific ethnicity.
Like the movie Stagecoach. If you set it in the real historical period of 1880, it's about a group of people traveling through Apache territory. The majority of the characters are going to be white because of the time. Like the southern woman who is traveling to meet up with her cavalry husband officer. The US Marshal. They probably should be played by white actors, but it's not really that necessary. The story won't change much. But the Apache warriors in the movie should be played by Native American actors.
They're Apache's. That's a key element.
But if you take this same story and set it in the far far future. And it's not a stage coach. It's a space ship. And the threat isn't Apache's, it's xenomorph-like aliens that only come out during eclipses...
Then you have the movie Pitch Black. And none of the characters need to be of specific ethnicity or gender. You can swap them around as you like.
