Why do black Americans have weird and exotic names?

Not really. Have you seen old Irish names? Different cultures' versions of normal are different. I Googled the most popular names in the world and the top 4 are as follows:

1. Maria
2. Nushi
3. Mohammed
4. Jose

You might not find them that common, but according to the world, they are the most common names. It also might be an act of rebellion, or reclamation, since most descendants of slaves were given the first and last names of their slave owners, which were quite often simple English names like Smith, Brown and Jones and their own names were lost over time.

See this Wikipedia article: https://en.wikipedia.org/wiki/African-American_names

Also check the "References" and "Further reading" lists at the bottom of the article if you wish to explore the subject in more detail.

When I was getting my Masters, I worked as a TA. One of my students was from Kenya. Another student came in for help and he heard her introduce herself. (It been over twenty-five years. I don' remember her name.) After she walked out, he asked about her name and someone else said it was from Africa. He responded: I am from Africa. That was not an African name.

https://www.bbc.com/news/entertainment-arts-56638260
https://faroutmagazine.co.uk/importance-thandiwe-newton-changing-name/