I want to test your reaction to a few things.

First, a Muslim called Sayful Islam who says he wants Sharia law in the UK. "It will prevent drug problems," he says. "It will prevent prostitution and homosexuality being promoted on the street. Society is full of every sin that every prophet came to forbid and condemn. It will all end when the Islamic state comes." My reaction: fear.

And now we have David Cameron attending a memorial service for the victims of 9/11. There is a wreath in his hand. In the background, you can hear a man shouting. "You are the ones that are the terrorists!" he says. "You kill Muslims and then you want us to feel sorry for your dead! We don't feel sorry for your dead." My reaction: anger.

Finally, we have a man called Tommy Robinson, whose eyes are blurred with beer. He has just been at a meeting of the English Defence League, the protest movement that opposes what it sees as the Islamisation of Britain. This is what Robinson has to say: "Multi-culturalism has worked. My goddaughter is black, my niece is black. We live side by side. It hasn't failed. Religion has failed."

And my reaction to that? I suppose – and I've had to think a lot about how best to describe this – my reaction is sympathy. It is certainly an understanding of why this racist extremist thinks Islam is a threat to Britain. He thinks that way because he has the reaction many of us have to calls for Sharia law in the UK or to protesters who shout over a memorial service for 9/11: fear and anger. And there's an umbilical cord linking all of those things – it pumps blood from the anger and the fear straight to the extremism.

Proud And Prejudiced (Monday, Channel 4, 10pm) did a good but uncomfortable job of exposing all of those emotions without, quite rightly, imposing any kind of context. It presented you with two unpleasant men – Tommy Robinson of the EDL and Sayful Islam of a small group of Muslim extremists – and let them rant. But it also left you free to react to their rants, and then react to your reactions.

In the end, both men condemned themselves with their insularity and truculence, but it was the sections on Robinson's group in particular that featured that old combination of hate and ignorance. "You're a paedophile!" screamed one EDL supporter at a group of Muslims presumably because, in his world, there is only one thing worse than a Muslim and that's a paedophile.

But the main point of the programme wasn't about ignorance. In fact, what Proud And Prejudiced and Channel 4's other programme on race this week, Make Bradford British (Channel 4, Thursday, 9pm), seemed to demonstrate was that extremism is not so much a problem of ignorance as a problem of maleness – perhaps because it's men who still feel the responsibility to protect themselves and their territory.

And the men's anger and passion demonstrated another thing too – that separation seems to be a basic human instinct. The instinct can go horribly wrong – as in the case of the EDL – but we all separate into groups because it's comforting, because we feel stronger. And that's the challenge for multiculturalism: making all of that work before Tommy Robinson and Shayful Islam hurt themselves, each other, or someone else.