I understand what you are saying, but why then didn't the writer apply the term "savage" to the "Western Hunter Gatherer" groups they describe earlier:
> By the mid to late 5th millennium, the peoples of Greece had diverged from their cousins. Europe was convulsed in a parallel set of conflicts involving tribes of WHGs conquering their EEF neighbors and establishing themselves as a new ruling class, catalyzing a new synthetic culture with their new subjects.
The WHG by your definition are just as "savage" than the Indo-Europeans but they are described as "conquering" (which is a term of glorification), and "catalyzing a new synthetic culture". In contrast, the Indo Europeans are described as "destroying" and "not content their new lands".
I have a hard time believing the intent, process, and outcome behind either circumstance was appreciably different from the other, at least in any way we can infer from archaeology.
If the term "savage" as used in the article is simply a matter of "civilization" and not brutality, then the Indo-Europeans should be considered far less savage than the WHGs, since they had created the spoked wheel and chariot technologies, and were pastoralists who practiced wheat/barley agriculture and animal husbandry - they were not forest-dwelling hunter-gatherers. In this way, they were far more similar to the EEF in lifestyle.
Therefore, I don't think that the author is using the term "savage" denotatively as you suggest, but rather is coloring their otherwise fascinating article with their own anachronistic opinions of the ancient Indo Europeans.