Zinc stopping the replication process in vitro is a lot different than stopping it in the body. It isn't as simple as you make it sound. What most practitioners would say about the drug cocktail being given is that it is adjunct therapy. It doesn't cure the disease so much as it supports the immune system and prevents secondary bacterial infections from overwhelming the patient. The other consideration is that ALL of those things taken in inappropriate amounts can cause great harm.
So don't drink the fish tank cleaner? Tastes so good with a hint of gin...