Not only kill you, insane pirate also fight to bitter end, and will not try to retreat ever after getting ship reduced to 10% hp it will continue to chase you around.
Ever if you managed to wipe half of their fleet, they won't let you go, they will fight as long as have ships.
When you let them go, instead of running away, they will "maintain contact with your fleet" just to attack again.
This ever worse with pathers, all ships with SO, not trying to retreat and fight to death, ever getting zero CR is no reason to retreat.
plus infinite respawn and magically created fleets, ever wiping every market of pirates and pathers won't prevent zergrushes on your colonies, well, wiping entire world won't prevent pirate raids.
how hell they ever created that ships if there are no world with industry left?