My cats had really persistent pinworms. Squirming worms coming out of your ass is super noticeable (and gross). I don't think that's likely to be the silent affliction ivermectin is curing.

This author just doesn't understand pharmacology. Ivermectin's anti- parasitical effects and anti-viral properties are incidental.

Ivermectin has exhibited antiviral activity against a wide range of RNA and some DNA viruses, for example, Zika, dengue, yellow fever, and others.13 Caly et al14 demonstrated specific action against SARS-CoV-2 in vitro with a suggested host-directed mechanism of action being the blocking of the nuclear import of viral proteins14,15 that suppress normal immune responses. However, the necessary cell culture EC50 may not be achievable in vivo.16 Other conjectured mechanisms include inhibition of SARS-CoV-2 3CLPro activity17,18 (a protease essential for viral replication), a variety of anti-inflammatory effects,19 and competitive binding of ivermectin with the viral S protein as shown in multiple in silico studies.20 The latter would inhibit viral binding to ACE-2 receptors suppressing infection. Hemagglutination via viral binding to sialic acid receptors on erythrocytes is a recently proposed pathologic mechanism21 that would be similarly disrupted. Both host-directed and virus-directed mechanisms have thus been proposed, the clinical mechanism may be multimodal, possibly dependent on disease stage, and a comprehensive review of mechanisms of action is warranted. https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC8248252/

Here's why it works on parasites:

Ivermectin and its related drugs act by interfering with the nerve and muscle functions of helminths and insects.[74] The drug binds to glutamate-gated chloride channels common to invertebrate nerve and muscle cells.[75] The binding pushes the channels open, which increases the flow of chloride ions and hyper-polarizes the cell membranes,[74] paralyzing and killing the invertebrate.[75] https://en.wikipedia.org/wiki/Ivermectin