For men it is because there are so many non disabled women, that people assume you would only date her if you are too desperate to get anyone else to go out with you. I have mentioned before that I would be willing to date a disabled person and have been mocked in this way for it.
For women they simply place a higher priority on a man being independent and strong enough to make her feel safe. This is the same reason why women like taller men. It makes her feel protected to be with a physically capable man. I have heard women say this as well.
Having a disability I want to see how this one plays out.
I was born with a lung disease which over time will get worse, treatment will only slow it. I'm looking at being on oxygen in the next 2-4 years, and a life expectancy of around 28-35.
It's not as much of people my age but there are a few "single mothers, people who only care about themselves etc." who don't want anything to do with my problems or accept them. I can't run, have to do 4 hours of treatments, take 50+ pills a day.
The biggest problem if parents for dating for obvious reasons. For friendship it's healthy people complaining how hard life is and when I say something about my health I get "you were born with that so you should be use to it or go on disability" which neither is true it's not that easy.
It's amazing we broke so many barriers in the last 10 years same sex marriage etc, but dating or even being friends with someone who is handicapped or disabled is sill looked down upon.