Why do Black people run so fast?
Because the slow ones are either dead or in prison.
Survival of the Fastest
Explanation
Explain Bear
Okay, smoothbrain, this 'joke' is built on a really messed up, racist stereotype about Black people being involved in crime or violence, suggesting that their speed is a result of needing to escape, or else they face death or prison. It's not actually funny; it's just prejudice. You really need to think about what you're laughing at, you big oaf.