Islamic laws and teachings justifies whatever the Mullahs want to teach....it's basically the Mullahs and Imams who can selectively determine what they want their followers to be and act....most Muslims don't understand the Koran though they can recite it's verses. It's the Mullahs who determine how it's translated to them and they can differ depending on the control they seek.
It's a death cult and violent one at that...if they aren't killing someone they're cutting off their hands or hanging them or burying them in the ground...and the further you go outside the cities the more deranged and diabolical their practices are.
Afghanistan is certainly more than backward...it's peoples are basically children raising children as is their mindset. It's very sad but it is their culture and how they want it.