Why are black people expected to share their culture?

Why is it that black people are expected to share their culture, while other ethnic groups are allowed to keep certain traditions exclusive to their own people? I say this, as I’ve seen other cultures have specific things, whether it be clothing/hairstyles meant only for them, but when it comes to Black or African culture, there’s this idea that it has to be open for everyone. I saw a tiktok of a white girl asking black people on the streets if she could wear braids, and she received a positive reception from both those individuals and those in the comments saying ‘’it’s just hair’’ or that ‘’it’s not that deep’’, but why is it that Black culture is treated like something that has to be shared, while other cultures can set boundaries and have them respected? Why can’t Black people keep certain things for themselves the same way other groups do?

Please do tell me if I’m flawed in my thinking, I’m open to changing my mind. I understand the sharing of culture, what I don’t get is the universal expectation when it comes to black culture. Especially considering the double standards when it comes to braids, being discriminated for wearing them and yet expected to share.