I do believe it is the responsibility of the rider/operator to be aware of their own abilities but as for society being responsible, I have a hard time with that too!
I fly helicopters for a living. Ninetynine percent of my flying is heli-logging wich many people perceive as being extremely dangerous. A study by the Transportation Safety Board of canada has shown it is the safest sector of aviation except for airlines. The main reason is that only experienced, qualified and trained pilots move up to flying these incredibly powerful aircraft. New pilots start out with low powered machines, receiving extra training and close supervision. Since biking is not a business the onus is on the rider to make himself aware of his qualifications. Therefore I have no problem with a government instituting a graduated licence system that ensures that bikers have training and start out on smaller bikes until they can prove their abilities. It will never be perfect but surely better than letting loose a novice on a 180 hp sportbike.
"A man's gotta know his limitations". Clint Eastwood
"Learn to do by doing". 4H Club
"Learn from the mistakes of others! You will never live long enough to make them all yoursef". Vortex (helicopter safety letter)
P.S. I know three heli-logging pilots who have been killed. One as a passenger in a non-helilogging accident, one whilst driving to work and smashed into by a stolen van and the third as a passenger in a car driving home from work - the driver fell asleep and rolled the vehicle. None of them contributed to the accident that brought their demise in any way.