I think that first paragraph suggests we assume there's something to fix. History from an Afghan point of view might be more "everything was fine, then the British came in, so we fought them. Eventually they left, and we did some of the things they left behind. Then everything was fine, till the Russians came, and we fought them, some of us. Then they left, and we went back to how things were".
The point is that nations are a construction, imposed upon people, and then we judge them according to that. But if you live nearer the Pakistan border than any Afghan town, the nation of Afghanistan means nothing to you, until and unless someone comes along and convinces you, or forces you, to pick a side.
Certainly agree on the latter. They are carefully saying they were not there to nation-build, because they know they've failed on that measure. But also, the only time 'nation-building' has succeeded is when you have a structure in place. That's why dismantling the Baath party in Iraq was such a mistake, and why Japan and Germany were so successful - no one told them how to be, just used the existing bureaucracy (and that's what counts). If there is no existing bureaucracy then, well, good luck with that - nations get forged in fire, conquest and war with others, mostly, to forge an idea of what the nation should be and no external power is going to force that to happen. And even then you need Westphalia to actually create the sovereign state - before that, bits of 'England' in 'France' is the least of your worries. In class once we ended up talking about states and their existence as if it were indefatigable, so the lecturer said "what's a natural state?" As in - where's an example of an undeniable state that was obviously going to be that way? Um, yeah, right. An island? Cyprus has two, UK mainland three (alright, four. Yes, okay, Yorkshire, off you go, too). etc. etc.
The public opinion thing is tough, mind - you can argue that a leader has to do what their people want. Be nice to see someone make a bold decision, explain why and bring people round. Immigration is a net benefit to the nation, let's keep freedom of movement, etc.