The article doesn’t say when all of this happened. Presumably it was some time ago. Putting Indian children in boarding schools happened in the U.S. too, during the 19th Century.
It’s hard to know how much of the bad stuff (other than sexual abuse, of course) happened because of insoucience toward Indians and how much of it was due to being in the 19th Century. Most of us today would recoil from returning to those conditions, even the best of them.
According to the article, the objective was to turn them into “white” kids. That’s not very likely, since it would have been genetically impossible. What, presumably, they’re talking about it teaching them ways that were typical of those of white people at the time; reading, writing, science, perhaps farming, undoubtedly religion. And, one assumes, the other side of the coin is that they were not encouraged, perhaps even discouraged, from carrying on Indian ways like hunter/gathering, warring on other tribes, and worshiping whatever gods they worshiped.
I don’t know enough about the settling of Canada to surmise, but in the U.S. the truth was that there wasn’t much alternative. The conditions for continuation of “Indian ways” were gone, and permanently for the most part.
But it was abrupt, for sure, compared to the history of other peoples. It took the Gauls at least two centuries to become fully Romanized. The Teutons, other than those along the Rhine, possibly took longer for their culture to change from hunter/gathering and endless war to settled agriculture and at least some degree of social order. The Japanese, of course, completely changed their economic system and much of their culture in a half century.
But abrupt change is hard. As we know, the Samurai class in Japan had it very hard when that social and economic order was abolished.