Playing A13 (win10-64) and decided to keep a 'dead' colony going to see what happens (all four citizens died fighting a fire when a power circuit shorted out). At the current point in time there is nobody in the colony except a prisoner and a cat.
While waiting to see if/when the prisoner (the only person in the colony) attempts to escape a single pirate showed up to raid the place. Since there was nobody to attack the pirate decided to attack a wooden door (all my doors are wood). Instead of attacking one of the two closed doors, however, the pirate decided to attack the open door of the room the fire had been in (I had all three doors propped open in an attempt to keep the temperature down; that plan failed) instead of pathing through that open door and south to the one closed door he could have attacked.
I see nothing wrong with attacking an open door. Raiders destroy everything, including open doors.