Why don't black people go to night school? Because they always get marked absent.
Okay, hold on. That joke is really offensive to some people, do you really find it funny?
It's a routine saying that you hear from African-Americans who have a job at night. They always get marked absent on the white attendance sheet.
You shouldn't make racist jokes about blacks people like this. It's hurtful and not funny whatsoever.
I don't know what you're talking about? I'm not racist.
You're telling a racist joke, which in itself makes yourself seem racist. You shouldn't be making jokes about black people looking different from you.