> there are thousands of mammalian viruses that don't infect humans that could be modified to infect humans via specific modifications of their target mammalian

> there are thousands of mammalian viruses that don't infect humans that could be modified to infect humans via specific modifications of their target mammalian cell-surface receptor proteins Are you claiming that's what happened here? What virus do you propose was modified in such a manner? Where was it sourced from? Why was it not on the published lists of discovered viruses? > as was done in this specific case of a bat coronavirus modified at its furin cleavage site to make it human-targetable Did you even read the comment you're responding to? It details why the furin cleavage site does not resemble something that you would expect humans to have produced.