There has been such incidents in the past that you are talking about. Yes, it's a reality. No matter how much we try to think of an utopian World, such things happen in an army deployment. I can quote of numerous Pakistani instances too, but I think you get the picture. In most of the cases the perpetrators have been brought to justice, barring a few, due to lack of evidences.
Now, having said that it is not the purpose for which army is there. It is primarily there to protect from infiltration and neutralize a possible 5th Pakistani attack. Internal law and order is maintained by the police. Why do we need so many, in comparison to Pakistani Kashmir ? Because of Pakistan's use of terrorism as a state policy. No such problem exists in Pakistani Kashmir because there are no terrorists there.
It's not an indigenous Kashmiri independence struggle. Had it been so, then we would have seen a few armed conflicts in Pakistani Kashmir too, isn't it ? And then you would have required your own troops too, just like you need them in Balochistan.
That's why I say, we should come out of our delusions and see it the way it is. Pakistan wants Kashmir for itself, shedding crocodiles tears for Kashmiris does not fool anybody. That's why, in 2010, UN removed Kashmir from the list of disputed territories.