An artist could create a story in which a white person dies and goes to a fictional and magical Japan or a fictional and magical Africa, and it wouldn’t be a problem because there are no limits to fiction. But if they made a story in which a Mexican person dies and goes to a magical and fictional Europe, there would be problems. Why are there no limits for white people in fiction, but are there limits for minorities?
Same reason for redheads or for the token white person in an all black production.
Example: only two white guys in black panther. One is a colonizer and the other is an idiot.