They are an absolute menace, especially for pedestrians, and they need licensing with a proper competency test, as other road users have.
Given that competency tests are doing such a great job at ensuring that everyone merges in turn at road narrowing, adhering to speed limits, stopping at pedestrian crossings, stopping middle lane hoggers, etc. then I agree with you [/Sarcasm]
Whilst I agree that there's a need for better cycle training, it's mostly so that those who aren't cyclists, or don't have family who are confident cyclists, are able to learn the skills to cycle well. In doing so they they will be more inclined to cycle rather than drive.