Sorry, Casio, you won't get any sympathy here.

As the driver said, sidewalks are for walking, and bicycles belong on the road, or in designated bike lanes. In backing out the driver is looking for pedestrians, and gauging his vision based on expectations of their speed. You were going much faster than a pedestrian (even a running one) and were probably well beyond the drivers line of sight as he started across the sidewalk.

In most cases of sidewalks with curbside parking, drivers back out of driveways in two steps. The first is to back across the sidewalk while looking for pedestrians while not extending beyond the shelter of the parked cars. This leaves them blocking the sidewalk, while they look for an opening to pull into the road.

I don't know Maine law, but here in NYS, you would have been at fault and responsible to damage to his car if you hit him. Sometime back we had someone from Denver have a similar accident and get cited by the police for the infraction.