Earlier quoted context omitted.
The only person who really understood how to do independent validation. Of course the code MUST be different.
Why is it not a good idea to first redo with the original code? Also doing an independent implementation doesn't mean you should start there - what if it doesn't replicate with the same code?
The paper is entered into the scientific record, not the code, which will inevitably become obsolete (old language, old frameworks, implementation details tied to old hardware or operating systems, maybe some source code will be lost, github will go out of business). If the code is necessary, then crucial details have been left out of the paper, so it is not reproducible (although there are some journals that let you submit code as an artifact).
Pseudocode is better, IMO.