I think there are two issues you don't address. Death is final. There's no later exoneration if you've killed someone and it seems pretty clear that this has happened. State and federal governments have executed innocent people.
The second is that content of this article itself. The author does not sound thrilled to be in solitary; but the author also seems to have found meaning in life. Do you think that the author would choose death over the life he has forged for himself? I don't think so.