CPython (the compiler) is the most popular implementation of Python (the language) like GCC, Clang, and MSVC (compilers) are implementations of C (the language). Other Python implementations include PyPy, Jython, and IronPython.

Nobody is "pretending" anything. These have all been around for 15+ years at this point. Your ignorance does not imply intent to deceive on others part.

The project has self described as CPython for many years.

It’s literally the name of the repo [1].

There’s no grounding to feign surprise or concern anymore.

Moreover, I have used PyPy for years to beat the pants off CPython programs.

[1] https://github.com/python/cpython

PyPy is a JIT-compiled implementation of a language called RPython which is a restricted subset of Python. It does not and has never attempted to implement Python or replace your CPython interpreter for most intents and purposes. CPython is the official reference implementation of the Python language and what you probably use if you write Python code and don't understand the difference between a programming language and its implementations (which is fine)