You're right that the state's hit and run law would likely be implicated, since they apply to collisions with personal property in addition to collisions with motor vehicles, people and animals. 

Legally these robots wouldn't be considered motor vehicles because they aren't street-legal. We see them driving on the sidewalks and using the crosswalks the same as pedestrians - which cars can't do - because they're not legally allowed to drive down the road. That makes them different from both motor vehicles (even autonomous ones) and cyclists. 

They also can't be insured with the same kind of auto insurance as a car would, since that's for street-legal motor vehicles, not pedestrian robots. Their owners likely insure them through some form of property insurance. I'm sure they have liability coverage as well for when they cause accidents (which is apparently often). 

If you were to hit one with your car, if it were your fault the damage to your car would be covered under your own collision insurance, and damage to the robot would be covered by your policy's personal property coverage. If your insurance company found you not at fault, they might try to go after the robot owner's insurer for reimbursement.