Yes, we have a shortage of transplantable organs. But that does not in the least excuse in prison self evident. (The story is unclear whether the organ donations could be live or would be restricted to cadavers. If “live,” it is an absolute outrage.)
China may treat prisoners as sources of organs. We should never get into that gutter. This is not to say that a prisoner should never be able to be an organ donor, but the donation would have to be freely given and without a hint of coercion or “time off for good donations.”
