You've posted one of the really early accounts of the Seattle incident. A few cyclists did get out of control, but not until the driver (who was parallel parked, not corked at an intersection) drove into a group of cyclists running one over and driving with another on his windshield. The driver has since admitted to initiating the aggression by revving his engine and claims to have accidentally popped the clutch and driven into the group of cyclists, though most people don't believe that.

The events after this were unfortunate and not excusable (the drivers tires were slashed and he was hit on the head), but have been explained as a reaction caused by the widespread notion that a driver who has injured cyclists, especially a hit and run, is essentially ignored by law enforcement, thus it would be necessary to detain him themselves. I don't think that is a good excuse at all for smacking someone with a U-Lock - you could kill someone doing that and I think the cyclist who hit him and the one who slashed his tires deserved to be arrested. The one thing I don't agree with is the driver has not been charged for assaulting the cyclists. No matter what his treatment was afterwards he should also be held responsible for his actions.

It does just go to illustrate though, how bad the incident with the NY police officer was. Things like that definitely reinforce the perception that the police have a bias against cyclists, are unlikely to help you and may even harm you. If the department does not make an example of the officer relations between them and cyclists will likely suffer.