reckless driving advice wanted

I'm not quite sure why the cop would have inferred that you were driving recklessly. If the other driver struck your vehicle from behind and then side swiped you, the damage to your car should indicate who was at fault.

If the other driver has no insurance that doesn't mean that he has no liability. There's a good chance your insurance company will go after him if your damages are severe enough.

If your description of the events is accurate, it sounds as though the other driver may have been intentionally trying to cause an accident when he slammed on his brakes in front of you. Had you rear-ended him he would most likely have tried to collect from you or your insurance company. He may be someone that's done this type of thing before. I've heard of scam artists that make a living doing such things. Maybe a search of public records would reveal past shenanigans.