CJ, it was born out of some discussions that I had with various people during the first few days of the Walton & Johnson controversy. When I was trying to explain who Stephen Hawking was, I got a lot of "Who?" Then I would say "You know, the guy in the wheelchair who talks about science stuff with the funky robotic voice," and the light bulb would go on for a lot of people.
Then later, when Clear Channel made its various proposals which didn't include an on-air apology from the dastardly duo, I was in a discussion with several CALS where I was the only one who didn't find the CC proposals acceptable. They were basically telling me to shut up about the CC offers and that we weren't going to get any better offers. They were stunned when I told them I didn't give a d*mn about radio shows and PSAs and that quitting without an apology was fine for the folks who were still walking, but not so fine for those of us in (or soon to be in) the wheelchair.
Finally, a new Fa ce bo ok group was started by another PALS who also had the "no apology == no peace" mentality and I was invited to join that group. I was kicking a few ideas around with him and the "I am the man in the wheelchair" meme was born. It's modeled on the scene at the end of the movie Spartacus, where all the slaves rise up and declare "I am Spartacus."
YouTube - I'm Spartacus (Ext. Length)
So, "I am the man in the wheelchair" serves two purposes for us. One, it is an expression of solidarity with Professor Hawking, the famous "man in the wheelchair" who was the subject of W&J's ignorant attack. Second, it is a rallying point for all PALS so that our voices don't get lost and ignored in fast-moving events like this any more, simply because our disabilities don't allow us to keep up with those ablebodied folks who appoint themselves to speak (or not speak) on our behalf and who patronize us and shout us down when we don't see things the "right" (their) way.