Judge de current situation by ethical standards of the present and judge historic ones with the eyes of those days. Eugenics was, once upon a time, seen like "good stuff" all around the globo, not anymore.
But we have an essential difference I think between the genocide that China stands accused of, which you yourself see as a "temporally relative evil" (yes the US did it, but it was a while ago), and the genocide of the German attempt to destroy European Jewry (which was also a while ago) that I think we would all agree is an "absolute evil". So perhaps the Economist have a point here.