Yes they are stupid. Especially cultural apropriation. Like seriously the vast majority of cultures are created by mixing two other culturals together. Hell american cultural is literally nothing but stolen ideas. There is literally not a single part if american culture not either directly stolen or heavily influenced by another culture. And thats perfectly fine.
"Cultures steal from other cultures," doesn't somehow immediately jump to "perfectly fine." There's, y'know, context and different circumstances. In some cases it's a natural mingling and trade and that's cool. In others it's exploiting other's culture for profit and erasing their identity. Nuance, context, and all that.
Basically it boils down to treating people with respect.
Minorities appear to have no issue appropriating everything nice about the country they live in. God forbid they share their tortillas or cheongsam with the gringo.
That's not remotely what cultural appropriation is, a strong culture selling it on purpose is very very different than the issue talked about. And selling those foods? Said cultures are fine with selling and sharing them generally speaking.
The term is not merely about siloing all cultures separately. It's about treating people from those cultures with respect to their stuff and not treating everything a culture has as fair game no matter the context.
See, I can agree with why people might not like that and even can agree with it to a certain point. It should be seen as poor taste, but not something you should have an internet mob harassing you to demanding you lose your job over.
What I don't have a problem with is someone dressing up as a Native American for Halloween. After all, we don't stop people of African or Asian decend from dressing up as European Knights or princesses- why should we then do it if someone wants to dress up as a Native American? It's all generally meant in fun.
The thing is, a Native American costume? It's normally 1) The ethnicity itself and vague trappings of it is somehow treated as a 'costume,' 2) The actual appearance is sort of a bastardized mish-mash of different cultures, and 3) the Native Americans have no say in it, no profit from it, and it gives people an image of their culture which doesn't actually match them.
Like, compare the difference between 'Ninja' being a costume and 'Japanese person.' 'Mulan' and 'Chinese person.' The fact that 'Native American' alone is the costume divorced of pretty much any cultural relevance shows an issue.
Our image of Native Americans is so genericized and marketed that it's just presenting an image which isn't them, telling people it's them, and making it harder for, say, a Lakota to
actually sell the image of a Lakota warrior or such to do so if they wanted to. Now if a group of Lakota decided to sell halloween costumes based on their actual history, with information about it, and sold it so as to spread knowledge of their culture? That would be an entirely different matter all together and that's fine.
That would be the equivalent of your European Knights and Princesses- and it doesn't hurt that Knight and Princess are sold by people actually of those cultures. The 'Native American' costumes are made by... the same people who make the Knight and Princess costumes.
Heck, I think a lot of people forget that Native Americans are living cultures and not just an old historical look.
Oh, great specific geek example! Chakotay in Voyager. They hired a consultant on how to do his culture. The consultant was a white guy who, it turns out, made up most of his material out of whole cloth to sound Native-y to other white people and was based on no actual tribes. Ever wondered why Chakotay's background was mentioned prominently early on and we had a generic vision-questy episode and that's about it? That's why. So a white guy took a job intended for a native, and as a result a character who was intended to represent and show Native culture on the screen failed to do so, and ended up with a bland background they couldn't do anything with contributing to Chakotay having little to actually do. Tell me that's not cultural appropriation.