No one is proposing to make it illegal. The point is respect. Charges of cultural appropriation come up only when someone has misrepresentative themselves as belonging to another cultural, or has used offensive stereotypes, or has taken advantage of an existing discrimination.

It's just interesting how many White writers want to add People of Colour or Indigenous People to their stories to spice them up. If they're there just to show a representative cross-section of society, fine. If their otherness is of integral importance to the story, fine but get them right. If they're there to titillate, that's not fine.

Like the Bechdel test, one can ask a number of question as to why characters from another culture are there and if it's fair usage. But we know now that Blackface is never okay. We know cheap racist and sexist stereotypes are never okay. Shrugging and saying it's only fiction isn't an excuse. Words matter.