The topic of cultural appropriation is a difficult one, because as you so clearly show in your examples, all culture is shared.
Heck, wearing garments made of cotton is a fairly new phenomenon for the most societies. The custom began in South Asia maybe five thousand years ago and spread to parts of Africa over a course of some centuries. But cotton did not become popular in much of the world until the European industrial revolution, during which newer forms of cotton textiles spread back to South Asia and Africa.
I guess it’s easy to look at cultural evolution like that over a course of centuries or millennia and not get emotionally caught up about it.
It gets harder when it’s new and happening right in our faces.
I think maybe you are on the right track when you suggest motive has a lot to do with it.
Are people parodying culture? Are they being respectful? Are they trying to springboard off someone else’s success without any genuine contribution on their own part?
What about white rap stars like Eminem? Is he allowed to emulate Black hip hop artists? Some people say yes because he added unique innovations to the art form. Others say yes because he grew up in Detroit, and hip hop culture was his culture when he was a boy. Others say he is appropriating something that doesn’t belong to him.
My own gut feeling is that evolving culture is fine so long as we all respect one another, but I acknowledge that questions can become difficult to answer.