Here's the thing about the burka: it's absurd. There are many reasons why people choose to dress as they do but this garment is ugly, restricts communication and represents a dishonest ideology. If covering everything except the eyes protected women from rape and sexual harassment, Saudi Arabia would be a feminist paradise, but that isn't quite how I'd describe the kingdom.

The notion that young women in tight jeans are "asking for it" appeals to defence barristers in rape trials and some Muslim clerics – an Australian imam compared them to "uncovered meat" left out for cats – but it doesn't explain why elderly women are sexually assaulted in their own homes.

The leader of Ukip in the European Parliament, Nigel Farage, has just called for a ban on the burka (I assume he means the niqab as well, since that is more common in British towns and cities). In France, the demand for a ban came originally from a communist deputy, demonstrating that the burka causes unease across the political spectrum, and has received public support. But while I dislike the burka as much as anyone, I don't believe a ban is justified or even necessary, given that the arguments for wearing the face-veil are so feeble.

What worries me is that this isn't said more often, out of reluctance to cause offence or fear of appearing racist. The niqab and the burka are symbols of an ideology, not a fashion statement, and we shouldn't be afraid of making a robust ideological response to them.

Here is mine. One of the most fundamental human rights is equal access to public space. Islam doesn't demand that men cover their faces before they go out, but its more extreme advocates place special conditions on how women dress outside the home. It's a typical example of patriarchal practice, based on the notion that women should be under the control of their male relatives at all times, and it's incompatible with any notion of universal human rights. It limits women's contact with non-relatives and maintains barriers between people who have different ethnic and religious backgrounds. (Of course it does. That's what it's for.)

In effect, a woman in a niqab is wearing a mask, signalling her deliberate separation from people unlike herself. It's hard to think of another form of dress which is so highly politicised – or so rejectionist of mainstream culture.

This is the point missed by liberal defenders of the niqab and the burka. I'm aghast when they say it's about personal choice, as though that removes the subject from the political arena; one of feminism's most influential slogans – "the personal is political" – exposed that as nonsense four decades ago.

No one is saying that women cover their faces for a single reason: a fairly small number believe their religion requires it, some come under family pressure, others adopt it for the political reasons I've outlined above. Whatever the motive, the symbolic meanings – separation, rejection, an acceptance of shame – remain the same. I don't want to ban the burka but I do reserve the right to say, as politely as possible, that wearing it in the 21st-century is preposterous.