Except that your analysis is not borne out in reality...
I have flown several aircraft with central control sticks from Cubs and similar light airplanes to fighter jets. I have also flown the AH-1W Cobra helicopter with a right-side control stick that moved (yes, actually MOVED) in the normal fore-aft and left-right axes. NONE of those were even remotely "painful." All of them fell naturally to hand.
No, a stick is pivoted at the floor - correct? And the hand grips the stick in the palm with your fingers wrapped around - right? This has a totally different movement and total throw, compared to a joystick type controller. The total throw is what... 3 inches max forward/back for the joystick. Very different and uses a completely different set of muscles.
I guess there are just folks that refuse to see to control for what it is - there is also a wrist rest - the arm doesn't move, only the wrist and fingers.