Blaming Sirion for it would be like blaming Perdan for having their northern border guarded by Bescanon, a river, and some tall mountains.
Perdan has enough holes to be won easily against as the last Perdan/Caligus/Ibladesh war showed.
You just need to adapt the right strategy as attacker.
In this case now, there is no strategy to defeat Perdan, everyone just waits for Sirion and to win with brute numbers.
