On the contrary, that is PRECISELY what this is. With minimal materiel and infrastructure, the raggies managed to murder 3,000 of the "enemy" with negligible losses to themselves. Tactically, 9/11 was an overwhelming success for the savages.
The point people miss is that if "warfare" in the raggie world consists of murdering civilians, then they have no high ground when the US murders THEIR civilians. If the Trade Center is a military target, then so are mosques. If commuter buses and trains are fair game, then so are madrassas, "safe houses," and cars driving along Iraqi highways. And if civilians are the enemy, then it doesn't matter if the animals at Guantanamo were wearing uniforms or not; they are still prisoners of war.
The raggies defined the rules of engagement. They can't very well balk when we engage them under those same rules.
If this is "assymetrical warfare," then that term is nothing more than a euphemism designed to sanitize that was heretofore recognized by all the civilized world as barbarism.