I'm pretty sure the Talibans (not to defend them, mind you), were already cracking down on poppy farming before 9/11 and the subsequent decade long war.
So how were they benefitting? Or do you mean to say the US and allied forces allowed mass poppy crop farming that was then utilized by the Taliban to fund itself? You know there is an alternative hypothesis: the US and other occupation allied forces tolerated poppy farming to pacify and win over tribal chiefs and keep corrupt Afghan officials squarely on their side. Maybe both were happening, who is to say.
I'm ranting but its honestly quite a fun class regardless, and I barely know how it works given im a total newbie to DnD rules. I exaggerated a bit, I'm making i work so far lol. But I will defo re-run as a fallen monk or a warlock but good but cooler than the (endearingly annoying) Blade of the Frontier next run.
Edit: also I know EXACTLY where you might have broken your oath in the first hour (because I did too).