If you fudge the crispness of the taxonomy by calling human policies a real variable, you are just going to lead to semantic confusion. You have confused the definitions of stationarity and ergodicity. Stationary systems merely mean that the value of the random variables are independent of the historical time. This implies that the historical date when an experiment is performed should not per se affect the outcome. Stationarity requires that the finite-dimensional distribution functions remain the same if the time axis is shifted.
Some stationary systems can be non-ergodic.
I will not get into the philosophical discourse on free will vs. determinism for it seems to me that you are only trying to muddy the waters. If my applause threw you off, I am sorry.