Explaining fashionable cultural appropriation to my fellow white people

A Facebook thread copy/pasted here as I may need it later

It's important to consider message is that one is sending. Wearing (1) objects of mourning/war/childbirth/diplomacy as a fashion/fetish/newage accessory, when (2) they belong to cultures that lack accurate media representation, which causes (3) the general public to mistake the former meaning for the latter is an act of intercultural hostility. It cuts short the ability of people to publicly express their own culture publicly without creating miscommunication - and especially because that miscommunication often entrenches existing stereotypes (e.g. Rasta being depicted as synonymous with "Chronic" rather than a religion; Cheongsams as sub wear; anything Aborignal being laid back nature hippies)

Example:
Person from dominant culture:
"Dude! Looks like you're all gearing up for an awesome kink party!"

Person from marginalized culture in traditional wear:
"This is a child's festival you ignorant a**hole"

By contrast, wearing something where the meaning is clear (a European funeral veil) ironically is fine, as, in this culture, most people (or at least most people with cultural power) know it's a funeral veil.

I would also assume it's safe to wear summer leisure wear as summer leisure wear. But, since I come from the dominant cultural frame, there are nuances I may be missing.