Yes that's exactly what I'm saying. If external code is less then some hundred lines of code, it would be better suited as a tutorial and people would be better at implementing those lines themselves. And yes, that's only my opinion.

Do you have any reasoning behind that opinion, or is it just unfounded religious zeal?

Why should somebody who wants to use threading have to know how to write a preemptive scheduler? If you want a tutorial in addition to the library thats fine, but many good tutorials also release their code as libraries. In open source world, releasing code as a library does not mean having to keep people from understanding the workings of that code. Why should people HAVE to learn how the code works to use it though?