Yes, but no one is ever talking about pypy or jython implicitly. They are always mentioned by name because they represent <0.1% of all Python usage and are relegated essentially exclusively to niche or experimental use cases for power users.

It’s a bit like arguing people should start saying “homo sapiens” when referencing “people” for added precision. It may be useful to anthropologists but the rest of us really don’t need that. Similarly, CPython is really only a sensible level of precision in a discussion directly about alternative Python implementations.

(although in this case the original post is about implementation internals so I’d give it a pass)

Also: https://micropython.org/

CPython, pypy, jython are not alternatives.

CPython is Python. The others are attempts.