That may be a bit strong. What can be said is that a lot of the initial media outrage regarding the residential schools in the last few years were based on possible gravesites, discovered using ground-penetrating radar. However, multiple excavations have so far been unable to confirm those gravesites at the scales predicted, some of them even turned out to contain no human remains at all [0]. That does not excuse anything, but I find it troubling how many fairly strong claims are made in this thread with zero citations/evidence to back them up.
[0] https://en.m.wikipedia.org/wiki/Canadian_Indian_residential_...