I would call this a great oversight.
Just think about it, player builds some airships, loads them up with airbombs and goes to the pirate base to bomb it.
What is the Pirate supposed to do to defend themselves?
Ubisoft, please add like 3 Flak Emplacement on the Old World and New World pirate bases, the fact you can bypass all pirate defenses and just bomb with impunity makes no sense, you can literally defeat an entire pirate faction by bombing and taking 0 damage...