This is an unnecessarily combative comment.
The author doesn't claim to be implementing the C++ standard library. They clearly say they are implementing a C++ standard library.
It's obvious from the context that they mean a hobby-scale set of basic datatype and algorithm libraries. It would take an uncharatible reading to not realize that they mean a lowercase "standard library", not "conforming implementation of the ISO C++ Standard Library".
The article literally says "It's my time, and I'll waste it if I want to!" and uses "pystd" as the namespace.
What makes his library “standard”?
I think the author pretty clearly means "standard" in the sense of "providing functionality at the same level as the C++ standard library".
For example, if I were to say "I'm going to write my own Dune", you'd probably understand that to mean my own broadly-interpreted sci-fi epic, and not literally a clone of Dune with Paul Atreides, the Bene Gesserit, etc.