The "pity response" to people with disabilities exaggerates the "they can do nothing for you" observation here into an absolute.
The sad truth is, if your response to a person with a disability does not rise above a deer-in-the-headlights-
charity-impulse than the vast wisdom we have to share from living a forced marginalization due to our difference will be inscrutable to you. The pity would then truly be that "there is nothing we can do for you."
An encounter with a person with a disability is a wake-up call from the universe.
It says, "This is you too. What are you going to do to see that you are treated with justice?"
Nothing about us without us.