Cook is between the force and the immovable object; between the highly agitated doubters and what he sees as the brick wall of the medical establishment, that he reasons he is in no position to challenge. Now he is being personally called out by the former; rock, hard place, ouch 
It’s a plausible defence; why does he have to advocate for their beliefs?
This would be reasonable if he stopped there. Probably he feels obliged to do a bit more than that - after all he does have a platform, one that he fully deserves - and justify his position further; trouble is, that involves engaging with the challenge, which can be a slippery slope.
From Twirlip’s quote:
" Fears about the threat posed by Covid to western health care systems do not look to me like a political or media conspiracy. Fears of that threat appear to be the consensus of the western medical establishment. It is possible that the medical establishment may eventually be proved wrong. But it is hard indeed to believe that they are saying what they are saying only because it is convenient for politicians – or even that what they are saying is what most politicians want to hear. "
I’m not sure I agree with any of this. Talk of conspiracies is weak; we all know that moves can be made, and nets can close, due to bias and self-interest - without any rooms having to be filled with smoke. The rest of the paragraph is an appeal to authority - in response to a challenge to that authority by less prominent voices. If Cook had delved into the areas of medical contention (admittedly, that’s probably everything) he would probably have quickly found that the medical ‘consensus’ is largely a political one, with opposing medical voices being suppressed by political ones whether it be government, medical orthodoxy, MSM, ‘social’ media or the new wave science and tech media.
There are two obvious areas in which the push by those western political/medical powers should be challenged, without referring to medical knowledge. One is that the Sars2 virus and Covid-19 incidences have only seemed seriously threatening at population levels for a couple of peak months. In the UK for example following the peaks of March to May, the weekly overall deaths have been back at background five-year averages for months. This raises the possibility that the lockdowns will cause more harm than the virus.
https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/deaths/bulletins/deathsregisteredweeklyinenglandandwalesprovisional/weekending18september2020
This spectre of no-crisis has been on the go from sceptical outlets like Off-G since the beginning; it had to be reined in around April when the ONS data showed that the reported deaths were indeed real, many and…extra, as Figure 1 in the above link shows.
But now these peaks have long passed, the argument is back. I think it’s extraordinary that the drop in death counts from about June did not result in a period of calmer discussion.
The other area of challenge that should be made is the greatly higher death rates in these countries where Cook’s western medical establishment consensus dominates. That these are rich capitalist countries is surely no coincidence.
Caution is often wise but I do also think that toes should be dipped in the water when it’s important. Good old Chomsky said the responsibility of ‘intellectuals’ (well it was a while back 
) is to tell the truth and expose lies. None of us were weapons experts in 2003, it was essential to consider what ALL the weapons inspectors were saying, and the politics too of course. Thousands of journalists write about medicine; even if you don’t know what’s what, you can still check out the dialogue between those that do, and report who is telling the truth, or at least what seems to be spin. Finding out who is suppressing who is an important game everyone can play, and is always of political interest.
It might be difficult if coming cold to a new area just as the heat cranks up though.