It became apparent really fast that ivermectin was effective... against a superinfection with parasites, which the reported success cases all had.
But by the time it became apparent, the correction didn't spread nearly as fast nor wide as the original information.
The problem is, most people lack the scientific literacy to understand how science works, and many newspapers have long since gutted their expert journalists.
Excuse me? Do you know how ivermectin works? Read up on it, it blocks ion channels in invertebrates. Not mammals. It doesn't do anything to mammals unless you reach extremely high doses.