Why do black people have white hands? Because everyone has some good in them.
What are you trying to imply about black people?
Uh nothing, except the obvious, that black people are bad.
It's not right to make jokes that imply that black people are bad, because it's racist and not true. Jokes like this reinforce the prejudice that some people already feel about black people. How would you like it if people made terrible jokes about you?