The reason Canadians don't care about their history is that the Liberal Party has carefully constructed a national antimyth that edits out all of the interesting parts - the wars, rebellions, massacres, and expeditions - in order to render Canadian history exquisitely boring.
Since it's boring, no one is interested.
Since they aren't interested, they don't look into it.
Since they don't look into it, they remain ignorant of it.
Since they're ignorant of it, the Liberals can imply that Canada is and always has been whatever they want it to be, redefining Canada on the fly according to the requirements of the postnational economic zone in the current year.
The biggest thing allowing this to happen is that most Canadians do not care about Canadian history. Some of it is understandable on a demographic level (25% foreign born) but for the others it is an apathy that is hard to reverse.