"Professor Dave," whom I've debunked once before on this site, made a video back when the whole "covid" myth got going, in April of 2020. The video features an attempt at debunking the idea that "covid-19" (and viruses as a whole) doesn't exist. I recall finding this "debunk" satisfactory, back when I believed in "covid."
The video starts with the "debunk" a bit after a minute in. The section nearly begins with an assertion, "viruses exist. period." Nice and dogmatic! No evidence yet...
Next, he says that we can see viruses with microscopes, and that a lot of people study them. A lot of people study them, and we can see them, so they cause diseases such as covid-19. But I haven't seen the evidence that this is true, only that many, many people believe it to be true, and that they study it and perform "science" (not to be confused with the scientific method) on it. I don't trust these supposed "scientists." So, the fact that they study what they believe is irrelevant to me. I haven't seen any study or fact which demonstrates that viruses cause disease, that "covid-19" is different from the flue or cold substancially, or that vaccines can help "cure" these diseases.
Anyway, then Dave repeats the assertion, "viruses exist." After that, he says that if we can't agree on what exists, we are really "in trouble" as a society. That part has absolutely nothing, even superficially, to do with whether or not viruses cause disease. At least the previous part was an attempt at evidence.
So, I remain unconvinced of this "fact" that only "crazy conspiracy theorist anti-vaxxer lunatics" deny. This guy is supposed to be an expert (althought, as far as I recall, not a real professor, not that it matters much), and yet he did not provide me with one study or fact to prove his point. Only dogma and strength by numbers.
Now, I'll take a look at a "fact-checking" website which superficially seems to provide a bit more in the way of "evidence" that viruses cause disease. "Fact check: Viruses harmful to humans are proven to exist."
The article features a "virologist" making quite a few assertions, just as dogmatic as "Professor Dave." Yet, there is only one citation. Everything else is strictly opinion. The citation linked to a page that, from my very brief skim-through, did not appear to provide any evidence or study for any claims. The Seven Laws Blog UK article, "Fact-checkers?," goes into detail about the ridiculousness of "fact-checkers" spewing their opinions as facts, and people just being supposed to accept the unverified assertions. I still haven't seen any fucking evidence that viruses cause disease. I also like the article's comparison of "fact-checking" websites and the "Ministry Of Truth" from 1984. I mean, someone calling themself a "bearer of the truth," who spews forth nothing but opinion and dogma with not even a shred of evidence, is pretty similar.