Of course not; but one could do their own research on old drugs.
Perhaps research the role of zinc in the body.
Certainly it is important for testes function - and has been used by the Life Extension Foundation for cold remediation in a sublingual tablet for forty years.. .
Of course, Zinc is an essential dietary element. And yes been around for ages and seems effective for many different conditions.
But there are a lot of people suggesting Zinc added to this regimen like the doctor says has a positive effect. Maybe it potentiates the effects of the other drugs, or increases the uptake rate or circulation or maybe it blocks the receptors outside cells to prevents the virus from attaching. I don’t know (someone I’m sure has a good theory).
As you said it does seem to help common flu symptoms so maybe it does have an anti-viral effect of some kind. It’s basically an ‘old wives tale’ people have used it for years - maybe centuries, like a shaman cure. Unfortunately there is no FDA style large randomized clinical trial proving that it works or its method of action that I know of. And nobody will pay to study it for profit because you can’t charge $400 for a bottle of Zinc tablets. Maybe if there was grant money, or maybe out of charity or generosity, but not for capitalistic reasons.