Why is the questioner a lefty - simply because the OP fit the biased narrow minded view of the poster similar to Hitchen's narrow minded mean spirited reply.
If there were a reward for self righteous hooey that piece would win it. Generally I have respect for Hitchens as he is usually educated, intelligent, and a bit logical, that was obnoxious and idiotic on a number of levels. The questioner raised a question that has behind it a real history as even Hitchens admitted in his reply, but he couldn't stop there, he has to then castigate the loonies who happen to be Muslim for evil actions. People don't wake up one day terrorists, there is a process and in a many cases a genuine grievance. Hitchens even mentioned that aspect. Are crazies not evident anywhere fundamentalism lives and grows and takes over the person? The termite metaphor was stupid as well.
"Terrorism require alienated individuals, a complicit community, and a legitimizing ideology motivated by a desire for revenge, renown, and reaction from the enemy." Louise Richardson
Sharmeen Obaid-Chinoy: Inside a school for suicide bombers | Video on TED.com
Philip Zimbardo shows how people become monsters ... or heroes | Video on TED.com
PublicEye.org - The Website of Political Research Associates
Amazon.com: Becoming Evil: How Ordinary People Commit Genocide and Mass Killing (9780195189490): Books
"We first kill people with our minds, before we kill them with weapons. Whatever the conflict, the enemy is always the destroyer. We're on God's side; they're barbaric. We're good, they're evil. War gives us a feeling of moral clarity that we lack at other times." Sam Keen