Not defending folks behavior. But 3 cases out of what are certainly numbers in the 10s of thousands it not much more taking the drug is hardly proof the drug is a failure. Given most of these man tend to have dozens of sex partners a year if not a night, 3 known cases is basically astronomically low transmission rate.
More realistic to basically say that it’s very effective but not 100%
Where there are 3, there are likely 30, 300, 3,000. These cases that float to the observable surface are more likely the tip of a much large iceberg.
It’s been found that ideal adherence to the drug regimen is extremely rare. After all, why should we think that those so irresponsible to have so many anonymous sex partners are going to be any more responsible in taking medication?
And imperfect adherence gives way to drug-resistant strains of HIV, which are certain to proliferate in such a promiscuous culture as that of the homosexual male.