PPRuNe is full of self-appointed sky gods, wannabes, sciolists, has-beens and never-will-bes with the occasional helpful and informative poster.
It's amazing how many of them pontificate from on high about subjects ranging from learning by rote every single symbol it's possible to encounter on an area weather chart to knowing the entire ATPL syllabus inside out, bemoaning the brats of today who only hit the bank enough to scrape a pass.
You seem like a fairly smart person - as you have realised, the signal to noise ratio in the various theory exams you will have to sit isn't always great.
A large amount of the content in some subjects (especially met) is helpful and important though, so I suggest learning the basics and more and trying to have a solid understanding of it is of value to any pilot. Learning the arcane symbology or the more boring and irrelevant details by heart - not so much.
As someone else suggested - do what you need to pass the exams, then do your best to keep learning and improving as a pilot to gain a more thorough understanding of the important stuff.
