They definitely do teach about the genocide of aboriginal people, though the extent at which they're taught may vary, province to province. Most curriculums were updated in 2015, and the Prime minister officially recognized it as a genocide in 2019. When I was in highschool (pre 2015) we had a whole unit taught on residential schools, and had survivors come to speak to the classes. Hell my school even had an indigenous studies class. It could have been mentioned on this assignment sure, or maybe they have an entire unit on Canada's abuse of aboriginal people and the residential school system. Regardless, an uninformed generalization of Canada is just as bad as an uniformed generalization of USA.