And I don't disagree. This is a very good explanation of why these thing are a part of aikido, and perhaps even a case for keeping them in aikido. But neither of those things, I think, answer the central question of the thread.
I think this is another false dichotomy. Physics are universal. They are independent of culture. But that doesn't mean that particular ways of utilizing physics cannot help us identify a martial art.
To the extent that they do, you are talking about something that is a cultural contextualizer.