‘only a sith deals in absolutes’ encapsulates the idea that jedi are clueless to what they themselves have become It's why so many jedi became inquisitors. They are not so different to the sith, but they never really stop to think about it
Only a Sith deals in absolutes : PrequelMemes
They believe ultimately that what they do is right, and that is absolute thinking.
The line itself is an absolute statement — the claim that only sith deals in absolutes — which makes the very core of it seem contradictory coming from a jedi.
It's a uniformly strange line, not only for the confusion it elicits but for its sheer clunkiness.