4 ideas
In January 2002 Pakistan arrested Zaeef, the Taliban's ambassador in Islamabad, even though he was an accredited diplomat who had held press conferences after 9/11. He says he was stripped and hooded in front of Pakistani officials and passed to US custody. He was held at Bagram and Kandahar, then at Guantánamo, and released in 2005 without ever being charged.
After the Soviets withdrew, former mujahideen commanders in Kandahar ran checkpoints where they extorted travelers and abused locals. The Taliban arose in 1994 as a local armed response to that predation. Their early support came from ending roadside extortion and insecurity, not from villagers signing up to an ideological program.
When the US put pressure on Pakistan after 9/11, the same establishment gave up its client's envoy to secure its own standing. On this account, a proxy's protection lasts only as long as it serves the patron's interests. Shared ideology or past loyalty does not extend it.
During the anti-Soviet jihad, religious students (talibs) from village and refugee-camp madrassas fought in their own fronts. Teacher-student and classmate bonds served as the unit's command structure. Years later these existing networks of trust and shared religious authority let the Taliban mobilize quickly, without building an organization from scratch.