I'm against any and all organ donation. So I don't support taking the organs of prisoners. But the author's problem here isn't with organ donations but with the death penalty. He's not saying that the prisoners or their families didn't donate their organs, he's saying prisoners cannot consent because they are prisoners.
The article also said that singapore and taiwan used to allow prisoner's organ donations until their were "bullied" into dropping the practice. So it seems like it is a cultural issue. If the chinese want to allow prisoners to donate their organs, who are we to say otherwise. We use aborted fetuses for medical experiments. Should china be allowed to force us to stop such behavior? Not to mention medical testing on poor people in africa, india, etc.
Is it any better to take organs from poor and desperate people? Use poor people for medical experiments?