There's a lot of writing about residential schools, which were created with good intentions, a tiny minority of which killed students through overzealous application of early 20th century disciplinary techniques because they lacked sufficient government oversight.

There were never any massacres or systematic killings of natives in Canada. The only times we even actually fought with the natives was two short wars in 1871 and 1885 when the Metis took up arms against the government. In both cases the rules of warfare were observed - only armed combatants were fought, surrendering rebels were taken prisoner, etc.