because it does the desired effect
firing across the working boundary and LoC wont subdue the Kashmir issue it has the exact opposite effect
it is being discussed in the international media and even gave Gen Rahil Sharif the chance to bring this up with the USA , blaming India very correctly, that its hostilities along the border are affecting Pakistan's operation in North Waziristan which was much demanded by the Americans.
General reminded the Americans what he told them already that Indians would stir up trouble along the LoC while it was busy fighting the terrorists.