A general error

Feminists create a box to place all men in and then fight the box they’ve created. Masculinists choose a description of all women and then complain about the description they chose. Racists decide to characterise other people in a certain way then fight their own description. 

These individuals judge selectively and then fight and hate their own judgments; out of the 7,000,000,000 people on Earth there are both strong and weak men and women (depending on how you define “strong” and “weak”), good and bad from every country (again depending on the definition of “good” and “bad”) so any general description will fail to capture all cases. Such generalisations are wrong specifically.

A similar error can be made with Parkinson’s; it is a highly variable disease so any prediction of its progression is creating a specifically shaped box, which sufferers choose to lie in. Such predictions are selective and have no hope of accurately describing the progression of your disease because the basis of the description has yet to include your case.