In some ways this is right, in some ways it isn't.

For instance, my math teacher assigns a nice little bunch of questions that have to be done (or you loose marks). Without doing any of them, I'd ace the test anyway (I know this from past experience), and they are basically just boring drudge work that does nothing but make me dislike the class.

But there is a place for some amount of homework. By the time you're in high school, each class is really only getitng a few hours a week (depending on what system your school uses) so some of them need to assign homework for teaching purposes. It can also be used to evaluate students. (Niether of which applies to the aformentioned dumb math homework)