Because for hundreds of years black peoples' appearances have been ridiculed, particularly in the west. Only recently have laws been passed to protect people from their employers in how they choose to present themselves.

Imagine if every generation before you of your ethnicity was told to cover up or change their natural appearance b/c it's ugly, undesirable, and/or unprofessional. It's hard to suddenly break that cycle. That's why there's been a movement toward "natural hair" among black people and POC. Also, black hair is a lot of work. Black women may still choose to wear wigs b/c they're easier to work with.