I’m not sure about nationality…unfortunately, we live in a world with borders, so citizenship/residency status matters for a lot of things. I don’t think it SHOULD, but given that it does, I want people to trust I’m “American,” even if I don’t look like it.

“Black” is a pretty important and powerful word right now, especially in the United States. It’s interesting to see how it interfaces with “African American” and Black immigrants from Africa as opposed to the descendants of slaves, as several people have pointed out in the comments. But Black people, regardless of background, get treated a certain way in this country (very unfairly) and so it’s a necessary word for the BLM movement and criminal justice reform to recognize that.