They're not racist, they're racist-lite.
The daughter with a black man fetish. The father who can't help but performatively support black people. The son who wants to show how tough he is by fighting the black guy. The party guests who think black people are just the coolest, or are overly interested in their penis size or physical prowess. The grandfather who never got over being beaten.
It's a showcase of the other type of racism that we don't talk about as much, the obsession and fetishization of a race.
"I wish I was black so I could be fast, or cool".
The two people who weren't diet racist were the scariest. The mother who just saw "we can steal black people and no one will investigate" was perfectly observant and willing to use systemic racism for her own benefit.
The blind artist literally couldn't see race. He saw the main character for who he really was. He saw, and wanted to possess his eyes. Creepy shit, but at least he was creepy as fuck in a not racist way?
They're all parodies of the worst white people.
I think the yardwork and maid bit is just why they were around, because otherwise it's just "why do you have two random black people living with you". Grandpa likes being fit, which is why we have the wtf moment of him just running around aimlessly when he thinks the main character is asleep.
The main characters friend basically tells the truth the whole time, whenever they talk. "Get out of there man, you're deep in some messed up ultra white person shit".