You neglect that supernovas and magnetar events are orders of magnitude more common than these focused jet events. When one of the former occurs nearby, there i

You neglect that supernovas and magnetar events are orders of magnitude more common than these focused jet events. When one of the former occurs nearby, there is no possibility of protection. Objects that threaten it drift in and out of range at random. We have been in range of such an object many times, and just got lucky that they did not go off at those times. Dust clouds shield you from some kinds of radiation, but make others radically more harmful. Jet phenomena are commonly long-lived, and avoided by steering away from where they point. You can steer only when you are moving. AGN jets come only from supermassive black holes, and we have only one of those. The only protection is distance, and distance is achieved by going. Gamma-ray bursts we detect have all been pointed at us, but all from distant galaxies.