Because they have the capability. None of them face a nuclear armed neighbor. All of them enjoy tremendous superiority when it comes to training of their soldiers to the assets employed by them.
The US fights for oil, the Israelis fight for their existance, the EU fights because it yearns for its older status, we do not desire anything else. Our existance is not in threat, we do not hold a significant advantage over the pakis, we do not want our cities nuked, we do not want to end up fighting a guerilla war in Pakistan, we got our experience of guerilla warfare from op Pawan and I can't say we liked it.
We do have enough of an advantage to conduct minor cross border raids and not expect a full scale war, maybe even precision strike against terror targets.
You can't take them out by force. They're honor bound to seek revenge if you kill their brothers, its right there, pakhtunwali..badal, all of them paly a role here.
South Asia is not the middle east, we're not fighting a bunch of arabs here.