Why didn’t they prescribe it to healthy people and see how many developed and see how they progressed to covid and the # of each that got it bad or mild, use groups with HQC and zinc/mag +D, testing those with it won’t tell if it makes it hard to infector blocks the infection.
Because that's not what they were testing? You can't give Ivermectin to all 5 billion people on the planet, but you could give it to most of the ppl who get sick. So it is useful to know whether it works if you give it to someone post positive.