Did you know that Oniontown is based off of Brooklyn, a borough in New York City? Let's compare them.

First off, we have the bridge in the top, definitely based on the iconic Brooklyn Bridge. The architecture is the exact same.

And then we have the rowhouses, a common aspect of Brooklyn's architecture.

Brooklyn is a borough commonly known for being much more in poverty and staved by gangs than the other areas of New York City, so Oniontown fits the basis perfectly.
It also makes sense why Papa's Scooperia is here, because ice cream is famous in Brooklyn and many unique dishes came from there. Maybe even cookie sundaes.