Why young men take to terrorism (specifically the islamic kind)?

Today, I read something funny on the internet.
It is well known that Islam allows polygamy (specificall, only Polygyny). So, there was this guy on a public forum who was saying something to this effect: “Muslims are allowed to have 4 wives at a time. Given the gender ratio, it means almost 75% of the [...]

Homecoming and a hundred deaths

http://www.cnn.com/2007/WORLD/asiapcf/10/18/pakistan.explosions/index.html
http://www.newsweek.com/id/56740
Could it be just that this bombing was an isolated incident, carried out by one senseless fundamentalist? If anything, it has just added to the drama of the former prime minister’s return, at the cost of a hundred lives.
Update 1:
http://www.rediff.com/news/2007/oct/19pak2.htm
““This was a terrible act of terrorism perpetrated by Muslims on Muslims. We are [...]