The issue is the way these wars are now fought. I gave the ISIS example precisely as it is the FIRST public demonstration of how proxy wars and terrorism is backed and used on an almost freelance basis by anyone who needs to for an agenda.
What started off as an attempt by the Saudis and Israelis each with their own independent agenda to remove an Iranian backed regime in Syria, to take an example closer to your home.. take the recent Indian elections.. there are normal regular folk without any ideas of Akhand Bharat who supported NaMo in his election because they saw the potential for economic uplift, and then there are those who supported him because they wanted a temple at the site of the Babri mosque.. it is very likely that these two parties would normally not associate themselves with each other, but because the means would fulfil both their demands they joined hands.
The same way the Israelis and the Saudis joined in with the Rebels to achieve a goal they both found beneficial. The Saudis have the most potent strain of the terror virus stored away in their vaults(which ironically they've spent years on ensuring does not effect their own society as much) and they had the funds to push it in. Since the removal of Assad favours most of the GCCs agenda of having Iran out of the mix.. they all pitched in. The US finds out and decides to take over from Israel in providing the funds in this free for all against Iran. On the ground, you have the basic idea of rebels against Assad but as such its just a huge petri dish with each trying their brand of killer virus to see what kills Assad. Lo and Behold, just as with all viruses, it left the dish..and backfired..but the important point to note was the petri dish.. in this case the guinea pig of Syria and eventually Iran. So anyone who had any beef with Iran, found this nice open wound with semi-controllable viruses teeming in it, all willing to do the work for a few thousand dollars. To a state looking to settle scores or press its interests against another state.. this is the proverbial gold mine; a colony of multiple use mercenaries all willing to die for a very modest investment.
Take that same mirror and apply it to Pakistan and the TTP. Here is an opportunity(that India did not create) of anti-state elements in Pakistan(who are always on the lookout for funds and training) that are willing to do some work(via Afghan mediators) for a few thousand dollars. ANY , and I mean ANY smart state facing a neighbour like Pakistan would NEVER leave this opportunity be regardless of any pacifist ideals they may have held(hardly so considering the Indian reprisal attempts in the early 90s). In this case however, there is a massive need to avenge a wound called 26/11.. or is it?
IMHO, the issue may have a little sentiment with 26/11 but has more to do with the aforementioned need to keep Pakistan out as a border threat, out of the Kashmir issue.. and embroiled in its own survival with its own cancer where it just barely lives on.. and essentially ends up being a non-issue to India.
The issue was NEVER who fired the shot first, but who fired the shots thinking of self interest first.. and that was Pakistan. regardless of the rhetoric of Indian and Pakistani leaders, the Pk Establishment knows/knew it, the Indian Establishment/Think Tank knows it.. and its just a matter of who heads that establishment/Think Tank to bring about changes in that cyclic tit for tat "argument" on who fired the first shot and who got hurt more. Each out to act more self righteous than the other and( humorously to any martians observing) getting offended by the other's "self righteous" behaviour.
The only difference is that one Establishment/Think Tank has generally been more astute and aware of how to behave in the world "classroom", and while the other may have been more wily earlier... eventually the teacher has figured it out. Ill leave out who is who.
You believe in the idea that a supreme being exists who controls the universe and all in it.. and yet have issues believing that a man hunted for years lived right under your nose and was killed in an operation and his remains dumped?