Yoreth:

For example: I've heard vague rumors that GWF Hegel concludes that the Prussian State (under which, coincidentally, he lived) was the best form of human existence. I've also heard that Descartes "proves" that God exists. Now, whether or not Hegel or Descartes may have had any valid insights, this is enough to tell me that it's not worth my time to go looking for them.

That's an extremely bad way to draw conclusions. If you were living 300 years ago, you could have similarly heard that some English dude named Isaac Newton is spending enormous amounts of time scribbling obsessive speculations about Biblical apocalypse and other occult subjects -- and concluded that even if he had some valid insights about physics, it wouldn't be worth your time to go looking for them.