> I would first ask what happened such that Denmark owns Greenland in the first place

I think there is some misunderstanding of the issue here. While Greenland isn’t fully independent, many domains, including social services and child protective services in Greenland are managed by Greenland itself, not by Denmark.

But the controversial tests described in the article did not happen in Greenland - They happened in Denmark, but they were considered unfairly biased aginst Greenlandic parents living in Denmark.