I think it's human nature to avoid strangers. Even though you recognize him, he isn't someone you are aquainted with and there is nothing to say you need to go out of your way to aquaint yourself with him.

Once I was walking and there was a man in my path handing things out to people who passed. I started to freak out that he was going to hand me something. As I got closer my mind was racing that I didn't want anything, but it was the only way to go, because I saw another man across the street doing the same thing. So once I came up to him, he tried to hand me a pamplet and I screamed at him to leave me alone and don't hand me things. He looked utterly terrified that I was going to hit him or something, instead I just ran away.

So, sometimes it's just better to avoid. I don't think it has anything to do with anyone being disabled or not. People like to point fingers, but you don't know what someone is going through in their own mind.