The short answer is that we don't have the data to distinguish between high-risk homosexual men who have riskier sexual practices, either through not using condoms or through any sort of intravenous drug use or any other behavioural risk profiles, and a different part of the community who are in monogamous, long-term, committed, safe relationships.
With the tools at our disposal as a government and as a scientific community, we have used a very broad brush stroke—and we know the community has many more different elements to it—so all gay men got lumped together. That's why I stated earlier that the original deferral wasn't a deferral, it was a lifetime ban. As the science has been able to demonstrate risk factors, and connected that to behaviour, we have been able as a country to get this blood ban closer and closer to no ban at all.