For a cyclist to kill a pedestrian, which is exceedingly rare, it would take a lot of speed and bad luck to result in a fatality
Oh good, pedestrians will only need to work about being seriously hurt then, but probably not dead.
If a cop sees a car run the lights, that car will likely get a ticket. In most cases that I've seen it's not that the laws are unenforced so much as there's nobody with authority to do so witnessing the transgression.