Many parents tell their children that schooling is important. Otherwise, why would they be forced to go?
French is taught in elementary and high-schools in Canada in large part because the country is officially bilingual. Although decisions are made largely on a provincial basis, the federal government provides funding incentives for provinces to encourage bilingual education. Not surprisingly, then, the decision to teach French is largely a political one, not one based on the immediate practical concerns of students who might be spending hours upon hours learning it.
Parents, for their part, engage in post hoc justifications for this. (A post hoc justification is one made after the fact.) Why are their children being forced to learn French? “You are forced to spend hours learning this language not because of a political reason, but because it’s useful.”
French is useful the way learning any language is useful. The large majority of people in Canada outside of Québec don’t speak French. In a place like Vancouver, for example, it is more useful to know Mandarin, Cantonese, Punjabi, Korean, Japanese, Spanish, and probably several other languages before one gets to French. That is, relatively speaking, learning French is useless for someone living or working in Western Canada.
Consider: one might be able to have some conversations with people in one’s own province in French once in a while. One might be able to travel to a country and better navigate the place or have conversations with people. One might be able to read literature one otherwise would not be able to. Yet, these sorts of considerations could be said for almost any language, and in many cases more so, depending on someone’s situation.
The usefulness of schooling in general is also often a sort of post hoc rationalization. Many parents think the idea of having several hours of free time away from their children is attractive (especially with something that has no extra marginal cost such as public schooling), as this will allow them to make more money, clean the house, or so on.
Since they like this idea, they then look around for justifications for sending their children to school: it teaches important and useful things in a better way (largely false – there are much better ways to spend one’s time), it’s important for proper socialization (largely false), it’s required so you can get into university (nowadays, this is false), and university is important so that you can make good amounts of money (again, largely false – what universities teach is largely inapplicable to generating money, and there is a large selection effect which skews average incomes for people with university degrees up, i.e., people who get into university tend to be more motivated and so on, and so tend to make more money – the causal chain is largely opposite of what most people think).