The graves were cemeteries, in which the wood markers rotted away with age (like many of the old cemeteries across Canada, particularly in the Yukon).
What blame goes around is borne by the federal government, including the government led by Trudeau's father.
The majority of the kids died of diseases such as tuberculosis, then ubiquitous.
Although misguided, the intention of the school was to take illiterate kids into the modern age to give Indian bands a fighting chance.
There were a handful of instances of abuse, which have been seized upon to buttress Canada's grievance industry, the purpose of which is not justice, but to beef up legal fees and to beat up Christian churches.