The insurgents have to resort to that sort of tactic, they don't have any jet fighters, helicopters, tanks, etc etc to fight back with, super ted.

This was never going to be a fair fight, because you have the most powerful military in the world beating up on a third world paramilitary fighting an occupation of their country.

How exactly is beheading people one at a time (which certainly keeps the casualty numbers down) more barbaric than bombing an entire nation into oblivion?

It is because of attitudes like yours, super ted, and mary garvey's, that we need the Geneva conventions, and to police the military.