in that it requires an inordinate knowledge of a culture before a person can start using the symbols of it, and even then you can be accused of misappropriation just on the basis of not belonging to the original culture.

Not quite, and this is something kb was getting at, too. I'm arguing that multiculturalism isn't that if you don't learn anything about a culture in the process. You could go in with that knowledge or go in with the hope of gaining knowledge.

If I choose to celebrate Irish culture by following a recipe for an Irish dish, I've gained a tiny slice of understanding, a small memory I can associate with the region. But if I celebrate Irish culture by painting my nose red and getting black-out drunk, I'm reinforcing a false stereotype based on my (America's) ill-conceived notions about the country. You might say that the hippie's stereotype of India is at least a positive one, but my view is that it's still rooted in the same absence of learning.

It's not quite the same thing, but there has a similar change in meaning to the word "Shah", which has transitioned from a title for Persian Kings / Emperors (which itself was taken from Sanskrit, iirc) to a surname within Indian and Pakistani culture. Maybe appropriation among distinct cultures, but all keeping within similar meanings of one another. Then there's Shahs of Sunset, which switches its meaning into an insult for pampered Persians. Though honestly, it's hard to take that example seriously because of just how over-the-top ridiculous the show is.

Still, we're going back and forth over the same few points, so maybe it's better to agree to disagree on this.