Left hooking means the driver will still be moving but has turned left up a street immediately in front of you.
I agree, if a driver comes past and has been able to come to a stop at the side of the road then 'on paper' it does seem ridiculous that you would cycle into it.
From what the two articles I have read on this state, the incident was not a left hooker...which is why my opinion is what it is. Maybe with more information we can make a more definitive and clearer opinion, but given what we are being told, I would say that the cyclist in the OP at least bares some responsibility for hitting the car in front...not that the driver is not responsible for braking the law, because he is.