Iran has its own interests to safeguard. That is how mature countries operate. On the other hand we the Pakistani populace at large are obsessed with brotherhood and ....... in the process we shoot ourselves in the foot repeatedly.
We lost the other half despite both being Muslims, we are at logger heads with the Afghans....Muslims, not at best of relations with Iran either.
We need to safeguard our interests as well. If it means shooting down intruding Iranian Drones, shoot the Son of a b tch down!!!
We have in the past helped out Iran on a lot of things that are not in the open including refusing to install coastal surveillance radars along the Makran coast during Mushi era when the equipment had already landed in Pakistan. The fear was that US might remotely eaves drop on Iranian movements!