I seem to recall that you also wouldn't fault the cop for stepping out in front of a motorcyclist and putting the rider's life in danger just to pull him/her over to give them a speeding ticket. Sorry, can't reference the thread as it was pulled down. Should the cop then draw his gun because he placed himself in a position that the bike was bearing down on him? In your mind, can a cop ever do any wrong? Are you sure you don't work for the SIU now?
A cop stepping out at a radar trap to point a vehicle is a different thing altogether, but again, if you are driving with any sort of alertness you should be scanning ahead, you should be in control of your vehicle, and you should be prepared to come to an emergency stop at any time because emergencies or other impediments to travel do not announce themselves in advance. If you do not have that alertness and control, you are more of a danger to yourself than the cop is.
A cop has a job to do. In the case of the 401 hooligan ride that was brought to a stop, if one of those bikes was deliberately bearing down on a cop who is in a choke point and thus blocking an escape route for the bike, should the cop just do an "after you Alphonse" routine and politely just step aside if the rider looks like he is going to run right through the cop? How does that work for any deterrent value in future for that rider or any that witness it?