"You're different because one or more of your physical attributes doesn't work properly, and that difference makes me uncomfortable but intrigues me at the same time" (prime perception of mainstream society, see The Cinema of Isolation, p. xii).
I would not go as far as attributing negative experience with other people to causes such as stigmatization and demonization each and every time. That itself would mean to somewhat demonize others. We are all different and not everyone has a great day always.
Yet there is little left to guess in a recent 2009 campaign of the Fondation de la Haute Horlogerie. There I feel that we are very clearly equated with fake watches and fake people. Yet, the question of authenticity is a serious issue not just in prosthetics but in society. What is it that we see as 'real'?
On the other hand, no other person that looks at me as disabled person would ever admit to stigmatizing or demonizing me because of visible disability. Yet, it is undeniably one of the bigger factors that may affect a non-disabled person and at the same time mostly outside of reach as this is a matter located anywhere but even remotely close to an acceptable dinner table subject.
And particularly initially - but also for some people still after two decades of being an amputee - the stigmatization and demonization by the public has something deeply terrorizing and intimidating about it. It is worth dedicating some time to this subject before starting to talk back.
Example: I regularly attend a swimming pool, and there, I participate in a club training. A while back, a well educated lady who also is a member of that club told me she could not swim there any more. She said it would deeply depress her to see "someone like me" swim so much faster than her. I then took that as a compliment and asked her whether she considered that I had been even faster when I had two hands and whether she was not at all depressed by the presence of such two handed and even faster swimmers in our club? - She did not come back to club trainings. Seeing a person with a visible disability outperform her was far more threatening than being outperformed even more by non-disabled swimmers. So, there appears to be a threat that makes people go out of their way.
Ultimately we will have to look at design principles from their social meaning. For that, both sociology of disability and design principles are relevant areas of observation.