I really appreciate the optimistic tone in your writing. Yes, there’s a lot of injustice in our world but for our own good, we often need to stop with the “gotcha!” attitude of calling out and canceling people for making subtle mistakes.
I don’t personally think cultural appropriation is always, always wrong. It would technically be cultural appropriation for me to eat sushi as a non-Japanese person, but I don’t think it’s wrong. Some people think wearing Japanese kimonos is wrong if you’re not Japanese, but many Japanese people actually appreciate tourists doing that; they see it as an appreciation of their culture.
My rule of thumb is to draw the line on things of religious or spiritual significance. I would not wear a Native American headdress because that is akin to trivializing another nation’s medal of valour. I would personally not practise yoga, but many people do and many Indian people don’t have a problem with it, so maybe my sentiment is unnecessary.
Another bottom line is to just ask members of that community! Good on your friend for doing that :)