Here is another story explaining how the Franklin character got started. It was the late sixties. It was time to add a black kid to the group.
Also, the word around the internet campfire seems to be that Franklin is on the other side of the table by himself because he ...[text shortened]... what some white people get up to when they try too hard to convince people that they're not racist.
Charlie Brown dwells in a very whitewashed world that was far from representative of
the USA as a whole even in the late 1960s. But it was representative of many parts of the USA.
All white neighborhoods (or schools) were common then and far from extinct now.
Charles Schulz was not obliged to make a demographically accurate picture of diversity in his cartoon.
The sitcom 'Friends' was very popular with white Americans and much less so with black Americans.
At one time, the network reportedly considered adding a token black Friend to the six white ones.
Michael Moore has said that adding such such a token minority would have made
the show much more phony and contrived. He said that, in real life, Friends like
Rachel, Ross, etc. move--and enjoy moving--in about an exclusively white world.
Oh, there might be a momentary nod to 'diversity' where Ross, for instance, goes
out with a woman of East Asian heritage and wants to sleep with her, but it's obvious
that would only a diversionary fling (his perk of being a white man), and she could
never fit in with the core of white Friends.
I believe that it's usually condescending (at best) to add a token minority to a story where
that character has no real function except to deflect charges of racism against the writer.