Clearly the article is not talking about the global history of policing, it’s talking about American history of policing. You can infer that because Jim Crow laws are American laws. They didn’t have Jim Crow in Sweden.

As for the history of American policing, again, the article acknowledges that American policing has 2 lineages that merged over time.

There are two narratives of how U.S. policing developed. Both are true.
The more commonly known history—the one most college students will hear about in an Introduction to Criminal Justice course—is that American policing can trace its roots back to English policing.
Policing in southern slave-holding states followed a different trajectory—one that has roots in slave patrols of the seventeenth and eighteenth centuries and police enforcement of Jim Crow laws in the late nineteenth to mid-twentieth centuries.

There’s no one “origin” to American policing.