The Clown Gang is based on the most frostbitten gang in all of Detroit. The Juggalos. The concept art of the Clowns is very similar to what the tattoos of the Members of this gang are in reality. Also, the Juggalo is a gang of Detroit, with which Carcer city is very familiar to us.

As you might guess, juggalos are recruited from not the most prosperous segments of the population (Detroit still remains a kind of Mecca for them). The subculture has been repeatedly accused of sympathizing with Nazism and chauvinism, since its backbone is the typical "white trash" and white drunkards. But, in fact, juggalos are international and do not distinguish by race and origin - there are black juggalos, juggalo-latinos, and recently, entire juggalo communities consisting of Native Americans have appeared. After all, when everyone's face is painted and everyone looks like crack clowns, it's not easy to determine race on the fly. It unites.

Can you point me to sources to learn more, or are you posing a theory?

Here's a look at this article.

https://disgustingmen.com/history/juggalo-gangsters