On the other hand, they are a mechanism for establishing a modicum of order in a school - and they are generally preferable on aesthetic grounds.
Anyway, here's how it appears to be working in Britain's schools today:
Teenager says, "I'll wear whatever the fuck I want!" They then 'express their individuality' by conforming scrupulously to whatever uniform their peer group has designated as 'cool'. How much of this the school is willing to tolerate is up to them but in the last twenty years they've been much more inclined to send said teenager home with a flea in their ear. This state of affairs tends to be supported by all those parents who aren't living in the 1970s, which in my experience is the majority.
If, on the other hand, the teenager says, "I'll wear whatever the fuck I want - and I've got God or the gods on my side", they often get parental support to the point of a courtroom. Then the court decides in favour of the pupil being allowed to wear whatever the fuck they want, provided this has been sanctified by religion. This then hits the national media. This particular case had to do with the supposed right to take a dagger into school... Cue 'liberal-left' bloggers talking about the problem with 'secularists' and the need for tolerance and so on. Take Dave Semple, for example:
"[The] principle – which I hold dear – is simply the notion that government should not respect any one religion over the others or over agnoticism and atheism. It is the view that the State should not attempt to impose moral values on us.No it is - and it touches upon another one that anyone claiming to belong to the left should also 'hold dear'. It's called equality. I say, "The world is flat" - you say, "Don't be so stupid". I say, "I believe the world is flat because God has told me so in His Book" - you say, "I respect that". This case is a species of that. It is the government - more precisely the courts - deciding that decisions based on faith are superior to those that are not. It's as simple as that.
This principle is not at stake in this case."