The road appeared to have been wide enough for you to be closer to the right side, thus giving the motorist plenty of room to pass you. I know you said you were going fast enough, but you can't change motorist behaviour--they don't like to follow cyclists. Sure you can cite your 'legal' rights and all, but in the end your own safety trumps any laws.

I've ridden in and out of parking lots hundreds of times, even Home Depot, but I've never gone down the middle of it like you did.