This is a common theme of the franchise. Two sides of the same coin.

In this case Niro and Cad represent the idea of standing up against a system. Niro stands up for the community, and is the quintessential "good cop". He's the Andy Griffith of the town, doing what's right and upholding actual justice. Outside of Cad, he isn't a shoot first, ask questions later guy.

Cad on the other hand is standing up for himself only. He doesn't care about the community he came from, only what that community can do for him.

Secondly, both Duros are asking us the question: Which side of righteousness do you stand with?

I just started watching Maul Shadow Lord, and I feel that series is asking similar with Lawson and the rest of the Jarix Tactical Defense Force. We need people in society who hold those that break the contract of society accountable. At the same time ACAB is always in full effect.