As a Christian (a horrible one at that), I'm curious about your #4 reason "Addiction to any particular ideology." What does that mean?
What I believe is a choice, a rendering of life experiences that have led me to my personal belief in one true God.
I firmly believe you should choose to believe what you want; I don't think Bible thumping helps anyone. But an addiction? I'm not sure I follow.
Extremism is a form of legalism. Extremism emerges when one is so enamored with a believe or idea that he studies the "straight and narrow" law of that belief system, judges others for their shortcomings based on that system, and then enacts cruel punishments to appease their god, hoping to be placed at a higher echelon than those around them.
It can come from bigotry, it is definitely a misconception, and I also agree there is a level of mental instability involved.
You haven't voiced a real solution though. There is no control when it comes to extremism! Too much control breeds rebellion, an extremist view that the governing body is wrong!
If, however, we can instill in our children a spirit of love, that would end all the hate on the planet. But you are forgetting that innate freedom of choice to love or not to, which if you really think you can control, you are sorely mistaken.
The solution is out of reach, until we all decide, as a people, to live by the golden rule: treat others how you wish to be treated.
Thanks for your brilliant suggestion...