I personally consider the 'no-virus' thing to be pretty much the 'flat-earth' of the biological field.  That is, a ridiculous diversion heavily promoted, by coordinated operatives, almost exclusively for the purposes of creating 'confusion, inefficiency, and demoralization.'

The Dr. Kaufman guy seemed like a sleaze from the first time I saw him.  When Kaufman went full Sybil Edmonds on Dr. Mikovitz, who I do have some confidence in, it pretty much sealed the deal for me.  Especially given the rhetorical methods he used in that encounter.  Sadly, people I do have some hope/respect for continue to get sucked into his web from time to time.

In the briefest of skims of the topic, I don't seem much difference between the common-sense implementation of 'terrain theory', and the basic tenets of 'germ theory' before it was simplified down to uselessness for modern academic consumption.  General ecology is such a fundamental element of all this stuff, yet it is deprecated to the point where most 'medical professionals' have never even heard of this field of science so it seems.

Another complicating factor is that 'viruses' have been horribly abused for at least a hundred years.  The are even invented 'virtually' out of whole cloth when something is needed to cover up an act of malfeasance (such as creating a truly impressive bacterial pneumonia while puttering around with 'vaccines' at the Rockefeller labs in Fort Riley.)  This because they are out of the range of study without very expensive facilities so you can say anything about them and few if anybody will be the wiser.

This legacy of scientific fraud and subterfuge around 'viruses' certainly contributes to the uptake of the 'no-such-thing-as-a-virus' crap among even people who are on the more scientifically literate side.  I'll cut them some slack for that reason.  I'll certainly entertain the hypothesis that there is no such thing as viruses for Spanish flu, polio, HIV, SARS-*, etc.  Or more likely that they do exist but are a minor element of the impacts which are broadly attributed to them.  I'd also entertain the thought that even relatively proficient scientists might get fooled by 'exosomes' and what-not from time to time.  Especially in 'the heat of battle'.  It's fundamentally difficult to understand some of this stuff with as much precision as with more complex creatures.