Yup, category theory is often called "general abstract nonsense" precisely because it manages to talk about many disparate parts of math (or programming!) in a way that purposely avoids any reference to the specific. To usefully interpret the above, you specifically need to know that your domain often uses the category (C) of types (as objects) and functions (as morphisms), and that this category features certain generic types (such as Option, List, Array etc.) as endofunctors - and then literally plug all of those into the definition and work out the result.
It's exactly the difference between (in an elementary context) a word problem, vs. the general theory of equations of type foo which could be used to solve any number of word problems - except replicated at a higher level.