It's not a coincidence that this miracle is only being done on animals, where the legal protections of medicine are less.
"Contact killing" is real [1]. A copper ring will definitely kill some bacteria/virus on the skin immediately near where they touch. Related, most copper solutions are considered hazardous waste.
Yes, penguin conservationists do this to scam the penguins... You didn't really think that one through did you.
Copper is a well known antimicrobial and copper paint is used on ship hulls as an anti-fouling layer.