imalemmy

you would be very hard pressed to find anyone Native American who is happy seeing anyone in a mass produced war bonnet.

I'd argue this is the exception, especially due to the history specific to the location where this kind of costume is common. Admittedly I come from a mixed East Asian background so my bias is based on people calling out appropriation for ao dais and kimonos and the like.

To me it seems like you're misattributing your reaction to those wearing the costume. I disagree that a person wearing a costume has the onus to research its history. That should be on the producer/retailer.

I also disagree that a consumer should buy from the source. It's a lot of effort and responsibility you're placing on someone that likely has no intent for offense, when it's simply easier and more reasonable to understand the context of the wearer and realise it's not really an issue.

It's obvious to me that wearing someone's culture as a costume is fucked up

Why is it fucked up?

an unfunny reference to a since forgotten peanut butter slogan.

Yep. Jiffy is only used for peanut butter. Great point!