Joan Smith: I'll dance in my heels at Tora Bora

On the video Khan looked exactly what he was: a young man dressing up to play at being a soldier

I'm not sure what the contemporary equivalent would be but I'm certainly up for cavorting on top of the Tora Bora caves in heels and my best Dolce & Gabbana frock. This isn't as frivolous as it seems: I can see why people are horrified by al-Qa'ida but it seems to me quite possible (and indeed healthy) to find its leaders ridiculous at the same time, just as an earlier generation both feared and mocked the Nazis.

According to the Daily Mail, which devoted three pages to them on Friday, the latest al-Qa'ida videos (featuring one of the 7 July bombers, Mohammad Sidique Khan, and the chief al-Qa'ida ideologue, Ayman al-Zawahiri) are a "chilling" declaration of war. In fact, they are examples of macho posturing, a demonstration of the hideous values of patriarchy in which desiccated older men (Zawahiri) send deluded young fools (Khan) to act out their militaristic fantasies. "We are at war and I am a soldier," boasted Khan, before killing himself and six passengers on a Circle line Tube train.

In your dreams, is all I can say. Khan was actually a teaching assistant from Dewsbury, West Yorkshire, the father of a young child who should have embraced life not death; his "war" consisted solely of murdering and maiming defenceless civilians on their way to work. On the tape, he looks exactly what he was: a young man dressing up to play at being a soldier.

Khan's speech name-checks God, the Prophet, Zawahiri, the Jordanian terrorist Abu Musab al-Zarqawi and "our beloved Sheikh, Osama bin Laden", with only token references to women. This is a perfectly coherent account of the jihadists' world, which is so sternly segregated as to make the American military look like a model equal-opportunities employer.

If I were to treat the al-Qa'ida videos as pieces of theatre, which is what they really are, I would have to describe them as amateurish, with no decent parts for women and abysmally low production values. I mean, those beards! Those grenade launchers! My dear, those hammy phallic symbols!

But they are more revealing than that. According to Gilles Kepel, the French academic who has written one of the most detailed and convincing accounts of the rise of groups like al-Qa'ida, the Islamists turned to terrorism in response to failure - specifically the failure of political Islam to create a mass movement. Instead, bin Laden and his followers have retreated into a fantasy about using terror to recreate the Caliphate, in which not just the Middle East but large parts of Spain would be under Islamic law. Few commentators have recognised that bin Laden's appearance in early videos deliberately recalled that of the Prophet during his flight to Medina in the 7th century, invoking a period of simple certainties - and a notion of gender that could not be more anti-modern.

It is in that sense, and that sense alone, that these tapes should be taken at face value. The world of men and guns they conjure up is exactly what bin Laden, Zawahiri and their followers want to establish, a social aim that has been given too little consideration in all the discussion about their "political" ambitions. You don't have to believe that women are inherently nicer than men (I don't) to recognise that the jihadists have adopted a particularly two-dimensional form of masculinity, one that cries out for feminist deconstruction. These cartoon warriors may be dangerous, but don't forget that they are also risible.