We all are disabled

The shortest answer is because we all are disabled almost equally . We as humanity the whole need to survive and in this fight the caring about each other brings up more possibilities for existance. That's why christianity was so successful. It gave people a new instrument to cooperate through empathy and in perspective of further human history it have laid the ground for the civilization's achievements, scientific, technological and cultural. That's why to care for disabled people means to care for ourselves whatever strong, healthy , happy and safe we would seem to be to advance us to new horizons from where our today would be no more then wild prelude of real existance.