Peace.Now
Desire for the Aakhirah
How do extremist groups get formed?
I don’t know how extremist groups get formed and like everyone else, I can only make an educated guess. What I do know for certain is that Islam does not play a role in extremism. Let me give an example of how extremism comes about. Look at the animal rights group and see how their love for animals pushes them to ensure that animals are not treated in a cruel manner. At times, these animal-lovers may even risk life and limb to highlight the issues at hand, and strive to save the animals proactively which I am sure that most would agree is most praiseworthy. Then you get another class of animal lovers who also detest cruelty to animals, however their methods are contrary to the ones just described. They target scientists who are employed to carry out animal testing, maybe terrorise their families at home, send poison pen letters and even threated their lives. The foundation of both of these methods are laudable, however the means adopted by the latter certainly are not advocated by any sensible, mainstream animal rights group, in fact they go against the very spirit of the purpose for which they set out and profoundly criminal and detestable. Some feel that extremist violence especially targeting innocents is a valid form of fighting aggression. Let us take for example the Tamil fighters in Sri Lanka. Their disagreement with the ruling party, pushes them to violence and even taking their lives, although the organisation is deemed secular by nature. I firmly believe that in a lot of people, extremism come about because there is helplessness, and where a person\group feels they are just being pounded day by day, without any country or group to take up their cause, hence they take the issue further by doing the unthinkable.
Before Israel was formed and under the rule of British Mandate authorities. The Haganah group though defensive in nature, it also split off to from the militant group Irgun (initially known as Hagana Bet) in 1931. The Irgun employed terrorist activities to further their mandate, the British military headquarters, the King David Hotel was attacked, which killed 91 people. Haganah, their original group, often (though not always) preferred restraint. More problems when Avraham Stern left the Irgun to form Lehi, (also known as the Stern Gang) which was far more extreme. Unlike the Irgun, they did not wish to co-operate with the British during World War II and even attempted to work with the Nazis to secure European Jewry’s emigration to Palestine. (adapted from wikipedia. search for Israel). The IRA more closer to home, are self explanatory.
As you can see from these examples, terrorism and extremism are not a monopoly exclusive to Muslims or Arabs, rather a failed ideology adopted by many groups.
Terrorism or extremism is certainly not limited to Muslims but all faiths and ideologies have fruitcakes 
List of terrorist organisations – From Wikipedia, the free encyclopedia
http://tinyurl.com/d3yf7
Hindu Extremism
http://tinyurl.com/ylxcdh
Christian extremist terrorism
http://tinyurl.com/ml8oe
Islam is a moderate religion. In the 13 years where the Prophet Muhammad (Peace Be Upon Him) and followers were terrorised in Mecca by his own people the tribe of Qureysh. He never ever advocated similar activities, rather he extolled them to be patient.
., the instructions of the Prophet Peace Be Upon Him) are as follows: “Do not kill any old person, any child or any woman”[1]. “Do not kill the monks in monasteries” or “Do not kill the people who are sitting in places of worship.”[2] During a war, the Prophet saw the corpse of a woman lying on the ground and observed: “She was not fighting. How then she came to be killed?” Thus non-combatants are guaranteed security of life even if their state is at war with an Islamic state.
To demonstrate how moderate Islam is, certain things which are forbidden, would become permissible if there was a necessity or a dire need. A medicine may contain pork or alcohol, but there is no viable alternative then one is permitted to use such medicine. If one is forced to eat a forbidden thing, because they would die then it would become compulsory to eat enough of that item in oder to stay alive.
“Forbidden to you (for food) are: Al-Maytatah (the dead animals – cattle-beast not slaughtered), blood, the flesh of swine, and the meat of that which has been slaughtered as a sacrifice for others than Allâh, or has been slaughtered for idols, etc., or on which Allâh’s Name has not been mentioned while slaughtering, and that which has been killed by strangling, or by a violent blow, or by a headlong fall, or by the goring of horns – and that which has been (partly) eaten by a wild animal – unless you are able to slaughter it (before its death) and that which is sacrificed (slaughtered) on AnNusub (stone altars). (Forbidden) also is to use arrows seeking luck or decision, (all) that is Fisqun (disobedience of Allâh and sin). This day, those who disbelieved have given up all hope of your religion, so fear them not, but fear Me. This day, I have perfected your religion for you, completed My Favour upon you, and have chosen for you Islâm as your religion. But as for him who is forced by severe hunger, with no inclination to sin (such can eat these above-mentioned meats), then surely, Allâh is OftForgiving, Most Merciful”.
The Qur’aan 5:3