I'm glad someone has mentioned the Me Too movement, because my objections to that are much the same as my objections to the theory of cultural appropriation being a form of racism. In both cases, trivial examples, which many people might dispute as being offensive, have been included with far more serious issues. So a hand on the back to guide a woman through a doorway is assault and a child dressing up as Tigerlily is racist. It weakens the case for taking serious issues seriously.
A lot seems to come from university depts where the big issues are an overcrowded field so academics needing to make a name for themselves have to break new ground and develop theories of casual racism and casual sexism, objectification and so on. And we end up with sombreros being banned at Mexican themed events, only black actors allowed to play Othello and dwarves played by child actors. Corn rows on white women are offensive and even courses in yoga are suspect.
The other problem I have concerns the issue of 'othering'. I agree with the concept, but surely taking the stand that it's OK to dress up as a national of a privileged country, but not as a national of a country that has suffered oppression is creating another barrier dividing Us and Them. Tigerlily is the only representative of an oppressed culture in Peter Pan, so, when it comes to dressing up, she's left out, discriminated against.
And, quite frankly, I'm sure that the residents of Window Rock couldn't give a damn about a little girl in the UK dressing up in the UK. But then, perhaps they're behind the times. When I was there, the local radio was full of excitement about the upcoming Miss Navajo Nation beauty competition. What would Mumsnetters make of that?