There are two kinds of developers... those who want a single framework that will solve all their problems and which they never have to look into... and those who like to understand one or more abstraction levels below where they're actually working.

Digging into a framework's source code is natural to the latter group, but utterly alien to the former.

Documentation written for the latter group describes mechanisms, design principles, APIs, etc. The former group instead requires examples and step by step tutorials.

Both will call documentation terrible if it doesn't conform to their expectations.