Stephen Hawking - Wait what?

Maybe because different people have different view points?

Someone who can walk normally probably sees Wheelchairs as a prison because they know what life is like without them and don't normally need them.

While others who rely on wheelchairs for various reasons see them as a escape from the prison of being immobile.

Neither side is right or wrong. An alien species that can levitate or teleport might see legs as a prison or curse. Its just a matter of perspective.