It depends on the extent of the disability, but if your job is to stand in a store and answer verbal questions, and you can't speak, there are probably better things to be doing with your life.
Consider the other perspective here: I'd posit that all else being equal, most people would rather not have to go to work every day, particularly if "work" is a crappy retail job. We force most people to work because their jobs benefit the rest of society, but if someone can't work in a way that helps others, why force them to do it? Because it's not fair to everyone else?
Because hard work is good for the soul? Screw that! Go read books, raise your children, live your life as best you can, and let the rest of us take care of you. If the situation were reversed, I'd expect you to do the same for us.