Why is this terrorism different from all other terrorisms?

In his review of a play in London called Talking to Terrorists, Mark Steyn explains why the terrorism we face now from Islamism is different from all other terrorisms:

Right now, “terrorism” means, for most of us, Islamist terrorism—New York, Bali, Beslan, Madrid—but by presenting a continuum from the Irish and Kurds to Ugandans and Uzbeks the play in its very construction is a sleight of hand intended to bring Islamism within the manageable framework of more localized pathologies. Whether or not one agrees with the IRA about the merits of a “united Ireland,” it is at least a political goal which one can discuss if one is so inclined. The Islamists, alas, have nothing to negotiate. This isn’t a big secret. All you have to do is take ’em at their word. For four years I’ve had pinned up over my desk the pithiest summation of their position—by Hussein Massawi, the former leader of Hezbollah and the man behind the Beirut bombings that chased the Americans out of Lebanon: “We are not fighting so that you will offer us something. We are fighting to eliminate you.” The men who blew apart their fellow British subjects on July 7 had no interest in “starting a dialogue.” They’d “talked” to us—to their fellow westerners—all their lives: We were their friends and neighbors, schoolmates and storekeepers. But they blew us up anyway, and, in the cold gray dawn of the morning after, Soans’s play expends too much of its energy trying to avoid confronting that bleak truth. In its desperation to corral the Islamists within the pale of traditional terror groups, Talking to Terrorists is useful mainly as a demonstration of the degrees of self-delusion educated westerners are prepared to descend to.