Firstly, the vast majority of cyclists are also drivers, so pay car tax. We have a car but use it as little as possible, including shopping with a bike trailer, bike commuting to work, using train and bike for longer journeys etc. We pay car tax but do far less damage to the roads than a high mileage driver, so actually we are subsidising them.
Secondly, there are bad drivers, bad pedestrians and bad cyclists, but it seems to be the cyclists that get all the bad press. Shall we also demand a licence for pedestrians who step out into the road randomly or start to cross the traffic lights just as they turn green for cars? Shall we prosecute every driver who blocks the pavement, parks across a bike lane, passes a cyclist too close or goes through a red light well after it has changed (absolutely the norm for drivers in my city to the point that I was shocked to cycle in a different city recently and realise there are drivers who stop at red!)
There are many responsible law abiding drivers, walkers and cyclists - and there are many absolutely selfish, indifferent twats. A a cyclist in a large city, I have to be completely focused every second because of the high chance of another road user doing something stupid that puts my life at risk. It is not just cyclists - it is every road user.
And while it is obviously unacceptable for cyclists to endanger pedestrians, and there should be consequences when they do, the reality is that a car is far more likely to kill. I think the figure are around 2,000 people killed by cars and 2 by bikes every year. That 2 is too many, but it is cars that cause real carnage on our roads.
So it comes down to - do we want to encourage or deter cycling and walking? If we want to tackle global warming, pollution and obesity, we need less car travel and more bike and public transport.
So yes, YABVVU.