Angry disabled people

Having a run-in with an angry disabled person is a weird experience. If an able-bodied person gets up in my face over something it's rare that I won't lash out straight back at them. But with a disable person, that feels kind of... wrong. Even for me. A couple of examples:
I was going through a doorway at a shopping mall when two guys were walking out at the same time. It was a fairly wide doorway so I didn't see much problem. You know how when you're passing someone you do that thing where you turn slightly to the side pulling your shoulder out of the way so there's more room for each of you? Well I did that as I passed and everything would have been fine if the other guy had done the same thing.
Except he didn't. So we smacked shoulders fairly hard. And he had the nerve to go off at me and start swearing when he was the one who made no effort to get out of the way. So I turned and was about to tear into him when I realised why he was so pissed off. It turns out he's blind. The second guy was guiding him by holding his elbow so the blind dud didn't have to use a cane or a dog to get around. He was wearing dark glasses but I figure we was a wanker who wore his sunglasses inside.
With the help of his friend the blind guy was able to walk confidently and quickly. Which was the whole problem. He was so confident I had no idea he was blind. So it was all his fault for not being more obviously disabled. He should have been more blind.
Another case: there's a guy in a motorised wheelchair in my neighbourhood and he has a very bad attitude. He also seems to have supercharged his wheelchair because I've never seen one as fast as his. He also drives it on the road a lot - I'm guessing that's because he wouldn't be able to open it up full throttle on the footpath. Plus he gets to vent his frustration at the world.
Again, I'm guessing that's his motivation. He's pissed off at his life and is more or less daring the cars to end it. He's faster than pedestrians but slower than cars and he's also hard to see when you're driving and he's zipping in and out all over the place so I don't think it's a stretch to say he's at least passively suicidal.
At first I thought he was a jerk. Then I thought about it and realised that given the lot life has dealt him, being pissed off at everyone and everything is a reasonable response. I know if I ended up in a wheelchair I'd be the angriest motherfucker around. I'd run over people's toes and if they complained I'd back over their foot just to make a point.
"HEY! What are you complaining about? I'm in a fucking wheelchair here! You could drive a fucking truck over my feet and I wouldn't feel a damn thing! Count yourself lucky that it hurts when I run over you. Now leave me a lone you working-leg-having motherfucker!"