Because the 3 are public figures and became so relatively early in life. They,themselves, may well consider other factors including PD shaped them and Fox has wrote about his PD but I think they are generally well known by the public for their fame rather than their illness.
I can only speak for myself as to what influence PD has had but looking back pre dx I think it has had enormous influence in the way it affected me, particularly the cognitive effects, anxiety etc.
So I look at it as something I've lived with possibly all my life (first known motor symptoms aged 21). I find that helps me to gain a perspective on it and takes away a lot of the fears.
I agree that if we are perceived as pwp or disabled by others that can be annoying if applied in a negative way.
Is there a positive way?
If we are seen as overcoming our problem then, we can be seen as inspirational.
I found a way to live with this illness by embracing it and looking for what it has given me rather than what it has taken. I don't expect everyone to feel the same or feel they have to be that way.
I think we redefine ourselves all the time based on our life experience.
PD for me has been an opportunity to challenge myself in overcoming the difficulties.