MSM blood donation policy may seem discriminatory, but it is pragmatic

Health Canada have just made it a little easier for gay men (or, in the technical language, MSM, or "men who have sex with men", an awkward phrase to say the least) to donate blood.
Starting in the 1980s, gay men were subject to a blanket lifetime ban on donating blood. Then, in 2013, a "donor deferral period" of five years was instituted, meaning that MSM could donate blood provided they had been celibate for five years. Just this week, this deferral period was reduced to one year, in line with policies in countries such as the UK and Australia.
The whole idea of such a ban or deferral period seems to hearken back to the days when HIV and AIDS were considered to be gay-only diseases. Many authorities, though, including the Canadian AIDS Society, see no reason for any restrictions at all on gay men donating blood, and claim that to institute separate rules for a whole segment of society is tantamount to discrimination (the Ontario Superior Court ruled in 2010 that the deferral policy for MSM is NOT discriminatory, because it is based on health and safety considerations).
As someone who lived in the UK in the 1980s, and so is also under a lifetime ban by Canadian Blood Services (on the grounds that I was potentially exposed to the BSE outbreak there), I understand this point of view. I also understand that donated blood cannot be tested against absolutely everything, so I have always just accepted this as an unfortunate turn of events that I could do nothing about. But surely HIV testing is a much more mainstream issue?
Every blood donation is indeed routinely tested for several infectious diseases, including HIV, hepatitis B and hepatitis C. However, Canadian Blood Services maintains that the deferral period for gay men remains because the testing is not 100% reliable, and specifically that there is a brief period shortly after infection when HIV is not detectable. Presumably this window of error also applies to people who contract HIV through other avenues than man-on-man sex, but the odds are apparently much longer.
So, although my initial reaction was that this latest tweak is just a continuation of an already discriminatory system, it does seem that there is at least some sound science behind it. If you want more details, look though the detailed Canadian Blood Services FAQ on the issue (they even address the part that I had the most problems with, namely why their policy is so broadly aimed at a whole segment of society rather than individual practices). I understand their contention that their policies need to be simple and easy to apply, and that they do not want to introduce policies that actually decrease their donor base. The new protocol is, then, a combination of science-based objectivity and pragmatism.