re: Astronaut who spent 197 days on the ISS shows how hard it is to walk again

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I think it stems from whether gravity causes the centripetal effect. I think you already acknowledged that it isn't a centripetal force. As I see it, an effect is dependent upon one of the natural forces or gravity, which is also just an effect of mass warping spacetime.

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A normal force with a wall or tension can be traced back to a natural force, it just isn't gravity. It's electromagnetic forces found within the chemical bonds that make up the structures holding together the wall and "pushing" on the structures inside of it.

But it isn't gravity.

The only practical example I can think of in which centripetal force is caused by gravitational effects is literally the force of gravity we experience. The Earth is rotating and we are moving with it, and the force keeping us from maintaining our tangential trajectory is the force of gravity, which in this case is one in the same as the centripetal force. But that obviously doesn't mean all centripetal forces are caused by gravity, just that if you have a spinning object, there must be some form of external or internal force keeping the object from flying off on its own trajectory. For Earth, it's gravity. For a ball on a string, it's tension in the string (electromagnetic forces between the chemical bonds making up the string).

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That was the measurement but I would contend that any margin for error in the measuring equipment would negate that as a firm conclusion.

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Well you know I have no idea what type of accelerometers they were using but usually space-grade stuff is top notch.

But even if you discounted that one experiment, there is an immense amount of evidence that centripetal acceleration is a phenomena and we know exactly how it is caused and how to quantify it. The only stipulation for artificial gravity is that the rotation that causes it is now taking place in a microgravity environment and not on Earth.