Can Someone Help Me Understand?

Why is it that when black girls wear braids its cool its gucci. Then when a white girl or someone who isn't Black/African American wears braids it creats controversy? Or if someome who isn't Black/African American, people start looking at them weird or saying they can't do that? I understand that some of these styles come from Black Culture, but why does it cause controversy and cause people to get upset when someone who isn't part of that culture wants to wear that hair style? I have a friend who really wants to put her hair in braids but is afraid people are going to shame her or say negative things to her. She loves where it originated from and how they look. I understand, there are times you want to do something other than wear your hair straight or in a pony or curl it. I straighten my hair because I love how it looks and it helps when its really hot outside and my curly wavey locks add another 20 degrees to the already 112 heat.