The late great Peter Brock said that it is best to just feel sorry for them as they will go through life as angry, stupid, ignorant morons, or words to that effect! I put it all down to in-effectual training and licencing. Unfortunately it's a price we pay for being a very mobile society. In know in training circles in NSW for forklifts, implements etc, people are not deemed in-competant, but NOT YET competent, implying that they can become competant, not that they might be a lost cause. I think that goes for the average road user too (unfortunately, some motorcyclists included) that really, they will never be competant, and it's not just through lack of driving/riding skills, it's the attitude between the ears!
:A
Most people don't think that it is a priviledge to have a licence; they simply think that it is a right, regardless of how dangerous they are.
If I were of politician, licencing would require 3 different levels of training, and stringent testing that actually tests the road skills of the driver/rider. I suppose as motorcyclists we do have a heightened awareness of safety, and that is something that the average car driver rarely understands and hardly ever get; they just see us as temporary Australians.....
Now if we all had "always on cameras" facing every which way, we could get revenge on these idiots by catching video evidence of what they do.