back in 2008, do you recall that phone allegedly made by Ilyas Kashmiri who pretended to be an Indian official threatening all out war on Pakistan?
TTP/ LeJ, LeT and Al Qaeda would love to see an all out war between India and Pakistan. it gives them freedom to operate at a massive scale.
look at the international trend where these ptreo-dollar fed fanatics closely follow invasions and civil wars in the middle east.
Kashmiri armed struggle was once based on national ideology and unsolved dispute between Pakistan and India on the bases of which both countries took birth , but in past few decades it has taken a new twist of sectarian / religious fanaticism where these people wont settle with just ousting India from Kashmir but ousting all those Kashmiris that dont follow their Islamic code
please allow yourself to absorb this, you would be doing yourself injustice if you say you got it. I would be lying if I say I understand it all but to my very personal opinion, for this new breed of militants, everything is theirs to take and the land needs to be purged of all the impurity in Pakistan this impurity is shia's, Ahmedis and Christians.
getting out of scope here but there is no clear cut explanation about the motive if LeT is to be blamed for it with or without Pak army's help.