Except for few ractists; there's no issue of international border recognition. If that argument was so concerning; given Pakistan's no favour by biased international forums, there would have been a lot of noise made against Pakistan but None... yes no one had the issue and will never be. Such a lame argument is merely to pump some nationalistic air into ethno nationalists.
Other neighbours of Afghanistan have no such relations the kind of level Pakistan has. Secondly, TTP was taken under their wings by previous puppet regime. We cannot ignore the fact that Afghanistan is not some strong security regime internally. Huge area remains unmonitored given the tribal linkages. At-least, we see a lot of hunting dispatching TTP & BLA every now & then. If it was that easy to get rid of such a cancer; whole NATO wouldn't need to sign a peace agreement after 20 years of their so-called war on terrorism. We have less threat by the Locals as compare to sponsored rent a terrorists. This notion alone is being ignore since it is much easier to blame in general and put it on everyone but not the root cause of problem. You just don't cut yourself from a society and bear more of threat and giving them a reason to be manipulated at large. One has to think big than the personal issue or think out of the box.
The regime did not the locals. Here we are looking at totally different aspects. You are calling upon the regime and installed puppets having no reason to live but hate Pakistan and I agree on that. However, to take down such a ruling puppet threat; one has to have favourable & plausible relations with locals/public. Don't you see how easy it was for Taliban to take over Afghanistan in matter of days? Because, they had their backing from public and no one cared about sponsored regime living on temporary NATO presence.