And here lies the difference: agile includes retrospectives. I
It's the only thing you need for agile. And if you don't have that, you don't have agile.
Well, it depends. I have seen many teams where retrospectives are basically a lot of personal mea culpas, people talking about what they did not do right, and it was mostly about how they should have done things differently rather than how the process or organisation could be adapted. The overall feeling is that agile works great, scrum works great, so if something went wrong it's because of the human factor and that's what should be fixed...
I don't know about communism, but at some places the implementation of agile sounds like a regime.