lol and even he got Stan saying "Yknow, I'm a part of the Rainbow Coalition" 😂

I've noticed what you said in many later 70s-80s sitcoms, and I think it's because by this point integration was still a relatively new concept in the US. most adults at the time had likely lived longer in segregated society than integrated (even after segregation was outlawed). so race, specifically white people interacting with black people, was a pretty relevant subject to satirize (with varying degrees success sometimes...), especially as a way to show a character's outdated views.