Education is a privilege. You wouldn't think that to see the way it's treated by large numbers of children, their parents, their teachers and the governments that control much of it, but it is. It is an enormous privilege because it allows you a great deal of freedom to work in more varied and more lucrative fields, and to choose where you do it, to think and understand, to enjoy art more fully and appreciate the world and man's place in it more deeply, to particpate more widely in civic life, to have power over others if that's what butters your parsnips, and generally you are more likely to be and feel free (for some value of free) if you have a good education.
The basic value of education is simply to be able to make a living, and it was for that reason that churches and charities began to educate the children of the poor (well, there were other reasons, too). And it was largely for this reason that governments began to offer basic education to everyone. They quickly discovered that it was very useful to have control of the minds of the nation's youth (and it was easy to control the teachers) and so they made it compulsory for all children to be sent to school.
This would have been a very big mistake if the intention had actually been to educate them, but it wasn't. In the first place that intention was to get people to take schools seriously, but it quickly became indoctrination. For many years teachers in most schools have had to dedicate a disproportionate amount of time to attending to those who don't want to be there in the first place. It would be much more beneficial simply to offer education to those who wanted it, rather than try to force it on those who don't.
Governments are extremely bad at doing things, and they are particularly bad at education. Successive governments both in England and in Spain have shown few signs of having the first idea what it looks like and what it is for, nor of wanting to find out. But it is true that some education is better than none. It is often gained at a very high price, principally in terms of time, but many people have become more than they would otherwise have been because of state schools.
Not everyone, of course, needs to go to state schools. Those who can afford private schools use them, because they are almost invariably better and you get to choose how your children are educated. Another option is to educate them yourself, which is what I would do (and which the British government is trying to stop people doing). You need time, some money, and a good education yourself to do it properly, but think what educating your own children means- not sending them off to waste six or seven hours a day, not having them force-fed whatever fashionable nonsense someone has decreed they must be told, not having them grow up in an artificially narrowed environment where they are often at the mercy of thugs, and see little of the real world; it means being able to show them anything you wish, to learn along with them, to remove all the barriers that an institution would create, and teach them to think in ways no government would allow.
And that's why they don't like it. Children educated at home are not subject to control, they cannot be easily measured, limited, made uniform.
Some children have no choice but to get what they can from state education. Others are able to choose a better, or at least a different route to learning. To stop them doing so is not a good thing, and we should not allow that freedom to be removed. It is too important.
The other day Old Holborn argued that all frontiers should be abolished, that people should be free to go where they wished. It was deeply refreshing to read, unlike much of what he says, and is even practicable (not so long ago the world did indeed work that way). In the same spirit I propose the abolition of compulsory education. It would be immensely liberating. Education law in Spain, and I don't doubt in other countries, has reached crazed heights, setting out in immense detail all kinds of pointless aspirations which have nothing to do with education, while largely ignoring real learning.