I'm not so sure it is benign. It would not surprise me that some driver somewhere would do a similar thing. One should not lean on cars at traffic lights, but he was doing no harm at all to the car and the driver decided to cause him physical harm. If this reinforced to one driver that they can do what they want to cyclists, then it is wrong. Nothing justifes intentionally hurting another individual.

I know I am taking this a bit seriously, but every little bit of physological leverage agianst cyclists makes a difference.