If you find yourself doubting whether anyone genuinely believes in an afterlife with 72 bashful virgins, you are a disbeliever in belief.
If you rely on the divine authority of the Quran for condemning ISIS, you are granting the basic premise of those whom you attack.
Religion constitutes a stumbling block to integration. By this I mean: integration in our modern, secular, liberal, democratic order.
Why? All freedoms to which religious believers are entitled are already secured in the Universal Declaration of Human Rights.
Harsh punishments await those who abandon the group: traitors are ostracized, shunned and tarred even by family members and friends.