I must say that the fierce reputation the Kohistanis have has much to do with their reportedly cruel treatment of the foreigners (mostly invading British Indian and Kashmiri Dogra armies) and some sectarian violence..
Otherwise they are a very likable people and I myself enjoyed their hospitality once on a solo tour up north back in 2008. And that too in the heart of the 'Crude and Cruel Kohistan', Dasu, Shatial and Chilas..
Once they knew that I was a teacher, the response and respect was phenomenal..