A hit and run is not an accident, it is a crime. I don't understand a police officer saying they won't investigate a crime on private property. They investigate if somebody breaks into your home, which is also a crime committed on private property. They investigate if somebody burns down your garden shed, which is on private property.

You did not have an accident on private property, somebody committed the crime of hit and run, it shouldn't matter where it happened. I would call and speak to somebody else, because if what you were told is true, they have just declared open season on all vehicles that aren't parked on the street!
Note the vehicle code does not differentiate between private property and public property in naming the offence. Besides, your f%#kin Chuck Norris, whoop some A$$.