Young men love to fight. They particularly love to fight in a good cause. In the 1930s lthousands of young British men- not street thugs, but scholars, poets, trades unionists, students- went off to fight in the Spanish Civil War, in a cause that only tangentially touched them- "for Communism and for liberty". They included George Orwell, the poet Laurie Lee and -fleetingly- W.H. Auden.
So what's so surprising about young British Muslims going off to seek martyrdom in Iraq?
Auden, who became tiresomely conservative in middle age, later disowned his poem "Spain". It's one long adrenaline rush. Strip out the specific cultural references and the overwhelming intelligence, and isn't this what jihadis feel?