I can't speak for Mr Snow. Speaking for myself, if I can see no danger from traffic coming in the other direction, it helps greatly to get a head start on the traffic backed up behind you. as soon as the light goes green, lorries, cars and buses batter past you and I invariably end up in the gutter or if by miracle I hold my position in the lane, I'm subject to horn tooting, abuse and aggressive driving.
Put simply, it is to put as much distance between myself and the traffic as possible.
statistics on the number of cyclists who suffer accidents by obeying the highway code seem to back this up. the number of cyclists who are hit by vehicles at junctions are quite staggering and certainly greater than those injured as a result of jumping red lights.
that said, it requires the cyclist to only do so when it is clearly safe, which I do.