>>6844604It's a bit more complicated than saying it was appropriation, I think. Frida was of mixed descent and she would have been considered Mestizo or mixed Mexican-European. Mestizo also means different things in different countries but for the purposes of Frida, we'll stick with how it was used in Mexico.
For a long time "Mestizos" were treated as its own second-class caste in Mexico, with indigenous people or more-indigenous-than-European Mestizos being the bottom of the barrel. At worst, they were scorned and outcast. At best, they were treated in a paternalistic way by being pushed to assimilate and give up their traditionally "Mexican" ways of life--such as their traditional clothing, although not everyone did, particularly stubborn were indigenous people who worked as servants.
Frida's family was somewhat well-to-do, and her father was white passing, so she was not socially on the bottom rung by any means. Just about when she reached adulthood, the revolution inspired a social movement (which was especially popular among artists and avant garde crowds) to "reclaim" Mestizo culture as a means of nationalistic expression under a single "Mexican" identity. Frida embraced this by donning indigenous and traditional Mestizo clothing. She based her now iconic style on what she saw her indigenous wet nurse and family's indigenous servants and other less fortunate Mestizo servants used to wear.
So it's not as blatant as "she was white and was wearing Mexican clothes," but "She was a well-to-do woman from a white-passing family who deliberately donned traditional clothing typically worn by indigenous people and servants, so she could use their only means of holding onto their identity as her way to express being Mexican" could be seen in an unfavorable light by those who want to do so.