All NPC's in threat 5 - 7 pirate activity SS's are deadly ranked, not elite ranked and are extremely easy to kill. I use threat 7's to farm for mats all the time.
Hell, you get tougher NPC pilots in the haz res than you do the signal sources. Though I will say the Ambush threat 3s that drop 6-9 ships on you can be a challenge even to a well equipped ship.