The Rationale...

We pass this set of traffic lights every single morning cyclocommuting.  The left set is for buses, the right set is for everything else.  Every single time I come down the hill, it doesn't matter what colour they are at, I just go through them.

This morning, there was a car sitting at the right hand red while we rolled past the left hand red lights.  He proper honked the horn I guess feeling we shouldn't have run the light.

Now the horn honking was done so instantaneously that there was obviously no thinking involved.

I, on the other hand, think about the consequences of the light run every day.  I always think how I would explain it to a policeman.  My thinking is that the whole junction there is designed for motor vehicles.  If you drive from the green light, you hit the stopped traffic on the main road.  If you cycle from the green light, you miss the stopped traffic on the main road as it's started up again.  Running the red light on a bike means that in general, you hit the main road as the traffic there gets stopped.