[bluetomcat]

A perfectly valid case for using a library is when it implements a huge standard that you don't have the time, knowledge or expertise to implement yourself. Think of zlib, libpng or libcurl. These are de facto "reference implementations" of the respective standards, so you'd better rely on them in order to be future proof.

> We have so many hobbyist libraries precisely because our languages and tools are so flexible.

I beg to differ. The (initially) small hobbyist libraries are often working around the deficiencies of the language/runtime/core libraries. This has been the case for JavaScript since jQuery. If a third-party library doesn't implement a format or a protocol, or an intricate algorithm, but rather tries to augment the language, that is a huge red flag.