Since I happen to believe that what is wrong with these people is not that they are Muslims (plenty of Muslims who do not go around blowing other people up), I believe that they have been taught at their home that this kind of behavior is OK. Take their father: he asked for political asylum on the basis that, as a Chechnyan, he felt unsafe living under Russian rule. He was granted the asylum 10 years ago, and eventually became a citizen of the US. Yet when his kids were running around laying bombs, he was visiting Chechnya! He even claimed that his son was “an angel, such a sweet boy”.
The Tsarnaev brothers were obviously anything but angels (unless I missed something and angels are supposed to kill people these days). The problem is NOT Islam. Islam is just a belief system with which we can agree or disagree, but one that represents a particular perspective of the Abrahamic revelation.
But one particular stream of Islam has become over the past two centuries the source of almost every extreme interpretation of the Quran; interpretations which negate those parts of the book which do not support their particular world view while emphasizing those parts which reinforce their beliefs.
At the end of the XVIII Century, Arabs throughout the Middle East were chaffing under Ottoman domination. Growing numbers became convinced that the Sultans at the Port were usurpers of the power that rightfully belonged to Arab rulers. Among these Arabs was Abd-Al-Whahab, who claimed that any modification made to Islam since the time of the Companions of the Prophet were null and void, and that Muslims were supposed to go back to the pure form of Islam prevalent in the VII Century. His school of interpretation was called “Al-Muhawiddun”, but became better known as “Wahabbism”. The Wahabbi living in the Arabian peninsula made an alliance with some of the tribal leaders belonging to the Saudi family, and this alliance would eventually lead to the formation of modern Saudi Arabia, where Royal succession is still determined today by an Ulema (religious tribunal) of Wahabbi scholars. The Ulema also has a say in the legal system.
The Saudi-Wahabbi alliance eventually defeated the Hashemite family, who, as descendants of the Prophet, were the Shariffs (keepers and defenders) of the Holy sites of Mecca and Medina. As the Wahabbi took control of the Pilgrimage centers in the early XX Century, they also gained great influence all over the Muslim world, while the wealth of their Saudi allies allowed them to establish Madrasas (religious schools) from Jakarta to Rabat. These Madrasas, of course, taught (and they still teach) their own interpretation of Islam.
Among those who embraced the Wahabbi philosophy was one Hassan Al Bana, who in 1928 founded in Cairo a religious movement known as the Muslim Brotherhood, a movement which would eventually control the great center of Islamic teaching of Al-Azhar University in Cairo. Many of those who later became leaders of the Jihadist movement see in Al Azhar University and in the writings of Hassan Al Bana their ideological origin. The Palestinian branch of the Muslim Brotherhood is known today by the name of "Hamas"
In the wake of this expansion of Wahabbism and its related schools of thought, other interpretations of Islam were, and still are, pushed out of the way. Many of the Islamic schools responsible for the Golden Age of Arab civilization and for carrying the torch of Hellenism during the European Dark ages, are today but just a memory – marginalized by the ascendancy of extremism.
If we expect to win the battle against Muslim and Arab Jihadism, we need -yes – to engage in dialog with those who are willing to look at their Muslim heritage with an open mind and make room for alternative interpretations of their sacred texts. But we also need to openly confront and denounce those who have hijacked a religion to make it the justification of their own irredentist and militaristic view of the world. While Jihadism is not Islam, it springs from it...