I'm not sure I'm down with this "explanation" in the article.
I have no problem calling the Sith, or at least their behavior, evil.
The Sith - or at least those we have seen in the movies - are power hungry, and practice behaviors that are inherently chaotic, unsustainable and ruinous: murder, deceit, using people as a means-to-an-end, etc.
They are behaviors we find in sociopaths.
Since (at least in our culture/race) such behavior is generally seen as problematic and bad, we rightly call the Sith/Sith-like behavior "evil".
I have no problem calling the Sith, or at least their behavior, evil.
The Sith - or at least those we have seen in the movies - are power hungry, and practice behaviors that are inherently chaotic, unsustainable and ruinous: murder, deceit, using people as a means-to-an-end, etc.
They are behaviors we find in sociopaths.
Since (at least in our culture/race) such behavior is generally seen as problematic and bad, we rightly call the Sith/Sith-like behavior "evil".