Bernard Lewis presents some of his conclusions about Islamic culture, Shari'a law, jihad, and the modern day phenomenon of terrorism in his text, Islam: The Religion and the People.[40] He writes of jihad as a distinct "religious obligation", but suggests that "it is a pity" that people engaging in terrorist activities are not more aware of their own religion:
Muslim fighters are commanded not to kill women, children, or the aged unless they attack first; not to torture or otherwise ill-treat prisoners; to give fair warning of the opening of hostilities or their resumption after a truce; and to honor agreements. ... At no time did the classical jurists offer any approval or legitimacy to what we nowadays call terrorism. Nor indeed is there any evidence of the use of terrorism as it is practiced nowadays."[41]
In Lewis' view, the "by now widespread terrorism practice of suicide bombing is a development of the 20th century" with "no antecedents in Islamic history, and no justification in terms of Islamic theology, law, or tradition."[42] He further comments that "the fanatical warrior offering his victims the choice of the Koran or the sword is not only untrue, it is impossible" and that "generally speaking, Muslim tolerance of unbelievers was far better than anything available in Christendom, until the rise of secularism in the 17th century."[43]
-From Wikipedia
By the way..Bernad Lewis is a British-American orientalist who is considered one of the West's leading experts.
However, with the emergence of Sayyad Qutb and the Muslim Brotherhood in the 1950s, violent jihad does have an Islamic justification, if only in the ancilary 30 pamplets of Qutb. They certainly do convince some that these are permitted or required by Islam.
Shrugging Jihad off like Lewis did is neither logical or practical.
I am reminded of kids who trend on entirely new styles of music, complete cultures, for years with their parents knowing nothing. Finally the parents become aware of a thing, perhaps only a word, that describes the sub culture.