Either that, or he knows full well the score, and it tweeting such statements in an attempt to demonstrate that he has no guilty conscience on these matters. So he acts as if he believes himself, that way he believes he looks like a "good guy" really. There is no way he can admit out loud, that he understands his errors, so better to keep trying to paint himself as the hero he wants to be!
Makes you wonder what it would take - what it will take - for people like MS to actually realise for real that they are simply wrong, and have been all this time? Is it that he will always insist black is white, not matter what? Utterly delusional? Even when a 100% positive biomarker is found and disproves the BPS crap? I suspect that when that point is reached, they will just find another way of reframing what they spout; in fact I get the impression they are trying to do that already in preparation for the inevitable, by pushing the notion that mental and physical illness are much more closely related than us lesser mortals realise.
It is a very rare person who can admit they were terribly wrong, especially in a professional context.
We know he is wrong, and trying to get him to admit it ought not be a goal or expectation.
It's never going to happen and it's not important.
He is the old guard and the new guard has already amassed and rushed the gates.
Best to leave him to babble into his drool cup in the corner while we get on with Reality.
This type of reality denier will never accept reality because their worldview and in his case reputation depends on him only accepting what he spouts.
Doublethink comes down to the need to defend a belief at all costs, as Upton Sinclair said
It Is Difficult to Get a Man to Understand Something When His Salary Depends Upon His Not Understanding It
The point being you can't convince someone who has a vested interest in not believing something he does not want to accept. The PACE team probably rationalized doctoring their results, we got a bad cohort, or we are making the results clearer, we need to rephrase so scientists understand, its all the same disease so depressed people and ME patients belong in the same study and so on. Its absolutely incredible the lengths people will go to to lie to themselves.
They believe their own lies and will use confirmation bias, personal attacks, reality denial, implicit or explicit threats, obfuscations, rationalizations, rephrasing, ignorance, changing explanations, sowing doubt or any device needed to protect their house of cards.
Educating them out of it is futile because its not an educational deficit, they have chosen to believe something at any cost because they are not wrong. If they are not wrong then education can't fix being right...
Once PACE is retracted and we have a treatment expect them to still claim there is a psychosomatic component, or they were right all along and the medication just works better, or its an adjunct therapy and so on. The only way to get this out of our disease is to show their malfeasance, get them discredited and kicked out of scientific circles. They will then believe they are just persecuted but no one (except the gullible) will put any stock in their ramblings anymore.