
Alden B. answered 04/01/19
Experienced Tutor of Mathematics and Computer Science
Speaking from a personal standpoint, I avoided libraries as a novice because I was more concerned with learning how to solve problems on my own than to have a library solve a problem for me. In my case, and probably the cases of many others, using a 3rd-party library is a "cop-out" and inhibits growth as a programmer.
There is also the fact that libraries often have to be compiled and linked (such as is the case with C++), which is often too complicated for a new programmer to deal with on their own.
Certainly, if a programmer is already struggling to manage concepts like loops, functions, pass-by-value, pass-by-reference, etc, then having to learn how to use an entire library is simply overwhelming. So yes, the learning curve is also a factor.