Why wearing a culture as a costume is problematic.

I'd suggest going to watch this video so it makes more sense, though I will explain it below.

The video was taken last September, and 3 black kids in a black neighborhood were at a mini mart to buy things, and the white cashier asked these kids IN THE MIDDLE OF SEPTEMBER, if they were going trick or treating. You know why? Because they were wearing traditional African clothing. The kids hurt, left and told their mother who came in to talk to the woman and got very mad very fast because the women tried to deny it, thus obviously knowing she was in the wrong.

Using other people's cultures as a Coachella costume, theme party costume, or Halloween costume takes the seriousness away from it and makes that culture into a joke and you get shit like this, where people think that you're wearing a COSTUME and not your own damn cultures traditional clothing. Though I suspect the woman was actually trying to make a racist joke, and wasn't confused on what they were wearing. In the video she tries to say "I didn't know what it was" but when watching it, again, I feel like she was mocking their clothing.

This shit isn't okay, other people's cultures aren't your damn party costume or your university or high school mascot. It's not okay, it's not funny etc.