AOG - to say that all Taliban men are the same - and guilt of such appaling cruelty - is the same as saying that all Marines are monsters because of the My Lai Massacre in Viet Nam - for which only one officer was prosecuted -
http://en.wikipedia.org/wiki/My_Lai_Massacre
the actions of one person do not equate to an entire body of people, it is simply not accurate or logical.
I personally have never criticised troops for killing Taliban fighters - I simply ponder the justification for the Allied invasion - but that is another topic.
The wording of your Question refers to 'they' - wheras in fact this is the action of one man, and is not based on his alliegence to the Taliban, but his own twisted extremist views.
Can this behaviour be tolerated? Of course not, but let's not let hysterical invective distort the truth of this dreadful incident, or allow it to be used to further the sort of religious hatred that leaves the UK and its allies fighting and dying for an unwinable - and frankly seriously flawed cause.