How many colored people does it take to change a lightbulb? It doesn't matter, they'll just tell the room that it's empowering to be black.
Is that meant to be a joke about black people?
Yes, but I don't think they would ever change the lightbulb even if they had the chance.
Thinking all black people are lazy is a racist stereotype and you should be careful about saying something like that. Making jokes like that can really harm other people and hamper the progress that the civil rights movement has made over the last several decades.