Textbooks are a great source for what little knowledge has been digested well enough and is popular enough to warrant a textbook. If your interests are a little more technical, you often don't have a choice but to read academic papers. On a very rough scale: to learn something you might learn at a university as an undergraduate, read a textbook, but to learn something usually only PhDs know, you need to read papers.

It's true that many papers are badly written, but (1) to emphasize: sometimes there is no other source for something, and (2) most books are pretty awful, too, you have to be selective with anything.

There's also the possibility that they simply don't subscribe to the sort of attitude that makes sweeping generalizations about topics with vast depth and breadth.