[spiffydave]

"but why it would work for covid doesn't make sense"

This is the way many treatments work. For example, hydroxychloroquine was a treatment for malaria, but doctors found that some patients with autoimmune disease had their symptoms lessened or eliminated as they were treated for malaria.

So, it has become a milder treatment for autoimmune disease in some cases. The scientific community doesn't 100% understand why it's effective for autoimmune disease, but there you go. It seems to work in many cases.

I say this not as an expert, but as someone who has taken it and it has worked for me. I don't care that the mechanism is unexplained.