for some very interesting thoughts on schools and schooling, read John Holt.
I wouldn't say that schools kill creativity so much as they foster sameness in thinking, hierarchical "proper" behavior, and a belief that learning is unpleasant, is something that is done *to* you, and that you would rather being doing almost anything else.
Historically it's worth noting that public schools coincide with the development of industrialization, and that the original goal of public schools was to produce docile, capable workers for factories and to reinforce the social hierarchy. The two main uses for the word "class" are for a group of children of the same age who share a physical educational setting, and for a socioeconomic group. In school there is a lot of social pressure not to socialize between classes - the "older cool kids" don't want to hang out with the younger "uncool" kids, and of course the younger kids look up to and wish to be like the "upper classes".
I could write a whole lot more on this, but I doubt that many people here are interested.