There is one author who does not use memcpy, strcpy, etc. He wrote his own "standard" C library routines. Others have used these routines; they are public domain.

The security track record on the authors internet-facing programs is better than most. In fact, I cannot think of any author writing similar software with a better track record.

Sometimes the most popular solutions are not necessarily the best ones for every purpose. Whenever I write programs in C from scratch, I use byte.h, buffer.h, etc., from the above mentioned author. I do not use memcpy.

In doing this, I am not a professional programmer and I am not writing internet-facing programs for other users. I am a student of C learning how to use C, the language. If I know how the language works, then it stands to reason I should be able to use a variety of libraries, including alternatives to the "standard libraries".

Otherwise it is arguable I would be just learning how to use a standard library, not a language.

The C language has utility on its own, as form of a notation, and it is that utility which I seek to learn about. Historical records indicate there was C language in productive use for some time before there was a "standard library".