Of course they did Richard, but there again they were fighting against the whole country and weren't really all that fussed about who they killed.

They went into the country with four times the number of troops and ten times the airpower and never controlled any of it. Primarily because although they've fomemented enough insurgencies in other lands, they'd never fought to counter one (still haven't, look at the hash they made of Chechnya), they were in Afghanistan with a conscript army much as the Americans had gone into Vietnam with, and guess what Richard? The USSR's Red Army had it's "Shit No We Won't Go Crowd" too. The ones that did go were badly trained, poorly equipped, poorly motivated and completely disinterested - that's the how and why of their defeat.

But if you agree with Peter K, I'd love to hear your examples of the Taleban's ability to kill British and American troops seemingly at will and with apparent impunity.