It took me a couple of years of "doing it wrong", researching some more, and practicing the act of notetaking to understand why some people are such strong advocates of zettelkasten. Thinking and writing down one's own thoughts to reflect on later is far more useful than recording the thoughts of others.

It makes total sense however that taking notes without synthesis is somewhat pointless. These are things you probably won't read again. The catch is I think many do both without really thinking about it in the form of commentary in notes.