What difference does it really make? He's not in prison because he is a psychopath, he is in prison because he murdered five people.
Whatever label is placed on him, is irrelevant.
The campaign team (and David) seem to be desperate to claim that he is not a psychopath, but they are rather wasting their time.
He may have been initially imprisoned for being found guilty of murdering 5 people, but, from what I've seen posted here, he
remains in prison because (in part) those who would have the authority to release him on the basis that he no longer poses a threat to society rely on the results of these tests (or their own interpretation of them) to conclude that he does, in fact, still pose a threat, because of his
perceived current psychological makeup. So the tests, and the labels they generate are, in fact, very relevant.
The whole process of "addressing offending behaviour" in order to be channelled towards "appropriate" courses is rooted in claimed psychological assessment of propensity to re-offend, and the same is true (perhaps even more true) for those maintaining innocence.
As I see it, it's not the labels themselves, but the use to which they can be put, that is extremely relevant, again on both sides of the argument