I think "economy of scale" captures it perfectly. Just like how a rabbit cage and a thimble-full of jet fuel are not a good model for the WTC fires and collapses. Heating and convection just don't scale linearly.
Looked at another way, human fat contains about 75% the energy density of gasoline, which is among the most efficient chemical fuels known to humankind. There's no reason at all to suspect a ghoulish device of this type couldn't work, feeble models nothwithstanding.
The argument doesn't really concern whether it would work - not even Holocaust deniers are stupid enough to argue that - but whether it would consume so much fuel and be so fuel-inefficient that the logistics would become impossible.
The same guy makes a huge fuss over the static crematoria. He has a surprise coming from me in due course as I can prove he totally misread a file of coke supply receipts, which he misused to argue there was insufficient coke to cremate as many as is claimed were cremated at Auschwitz. Naturally there are further scientific imbecilities, especially fancifully invoked 'thermal barriers' which supposedly say that you need at least 20kg of coke per body, which then is defined as an adult Western male rather than remembering that a very high proportion of the victims were in fact, children.
My colleagues elsewhere have delved into some pretty gross detail, investigating mass incinerations of livestock and the like. Those are far more obvious real-world models to use for comparison, and they show it's remarkably easy to burn substantial piles of mammal, efficiently and relatively quickly.
There is a further argument to personal incredulity-pseudoscientific argument invoked, namely that witnesses mention the use of human fat running off from the pyres, to stoke them. I.e, not simply the added energy released by the combustion of fat, but the capture of run-off fat and then its return to the fire. This provokes much scorn from deniers.
'Common sense' says the situation is not vastly different from ordinary stove or barbecue cooking, but as we know 'common sense' may not always be correct.
I have wondered when in a morbid mood how much of the fuel in WTC came from this source? Horrid to contemplate really, but many victims were literally obliterated.
It is horrible to contemplate, but in itself surely a fraction of the total thermal energy that was released. There is however a parallel with the usual fire-can't-melt-steel debate, namely that the temperatures reached in some pockets of the WTC fire would have perhaps been sufficient to achieve a funeral-pyre combustion to the point where bodies could go on burning.
Anyway, gross-out out.
