This thread is just stupid and is based around an unquantified assertion. Yes, some cyclists ride on the footpath, but some cars go through red lights and some pedestrians walk out onto the road without looking. It hardly means that all do.
Cycling is not only a way of keeping the population more active and healthy, according to the Dft (with old data - circa 2007) there are half a million cycle journeys each day in London alone - how many of these are on the footpath? Practicalities aside I hardly think they could be the majority.