FOB Keating attack repulsed

[AmericanPride]

"Somewhere a True Believer is training to kill you. He is training with minimal food or water, in austere conditions, training day and night. The only thing clean on him is his weapon and he made his web gear. He doesn't worry about what workout to do - his ruck weighs what it weighs, his runs end when the enemy stops chasing him. This True Believer is not concerned about 'how hard it is;' he knows either he wins or dies. He doesn't go home at 17:00, he is home.
He knows only The Cause.

Still want to quit?"

I won't make any claims to how widespread it is, but I have experienced on multiple occasions either a complete ignorance of the capacity, resilience, and experience of the Afghan insurgency or an injurious under-estimation of their abilities. This is of course not to be confused with issues of legal or moral legitimacy, but we must recognize the fact that the insurgency has managed to effectively destroy a COP and nearly overran a vehicle patrol base (FM 3-90 defines destroy as "physically [rendering] an enemy force combat-ineffective until it is reconstituted."; and for awareness, defeat is defined as "when an enemy force has temporarily or permanently lost the physical means or the will to fight" and "the defeated force's commander is unwilling or unable to pursue his adopted course of action").

Is there difficulty in the Army/military/American culture in accepting that an enemy is capable of inflicting serious harm on us without our having made a serious or grave mistake that enables them to do so? Is the Afghan insurgency so weak that it's successes can only come from when we make mistakes? Does this affect our capacity to make accurate assessments of the situation and to craft effective COAs?