Muslim clerics reflect the views of their constituents. Most are moderate, and express moderate views, but Al Sadr and his Shia activists get the headlines in Iraq.

The Pushtun peoples of the 'frontier' states of Pakistan and adjacent Afganistan, primitively biblical but overlain by Muslim religion in their beliefs, feel under attack. The government in Kabul, an enclave with different beliefs, does not represent them. The government in Pakistan does not represent them.
Their young join the Taliban.

All of this has less to do with Muslim belief than it does with preservation of culture, yearning for self-rule, and anger and frustration at domination from outside.