Society treats the physically disabled with kid gloves. When someone in a wheelchair goes past, everyone DELIBERATELY says hi and acts super-nice to them, as if to say, "See, I'm nice, I'm not prejudiced..." etc. I may have imagined it, but I got a few glares for NOT doing so once. I felt like saying, "Excuse me, I'm not going to fake politeness just because he's in a wheelchair. I'll be just as seemingly rude towards him as I am to everyone else!"
Yet the mentally handicapped (with the exception of the severely ret*d, who are either mocked or pitied) are just ignored. Once I said to my dad that it's unfair that we have to be sociable to get through life, cos that's like saying to someone in wheelchair, "Get up and start walking or nobody will employ you!" He said that it's different because AS can be "controlled". I tried to explain that it's not as simple as that, but he doesn't seem to get it.
Anyway, OP, it sounds like the person you mentioned was being extremely rude. "I'm disabled, you HAVE to get up for me, here, I gots proof!" It's like, WTF? If they'd asked politely it'd be fair enough, but what you described sounded like she was being really disrespectful towards you.
_________________
'El reloj, no avanza
y yo quiero ir a verte,
La clase, no acaba
y es como un semestre"