Gay men are often stereotyped to have a lot of changing sexual partners, which increases the risks for STIs. There are quite a few countries that forbid gay men from donating blood because of this.
Now whether the ban is effective or necessary is another debate, but it's a legitimate public health debate. Not just an attack on homosexuals driven by ignorance.
The reason for the questionnaires is that a recent HIV infection won't always show up even with the best most sophisticated tests.
So we do the best we can to screen out people who are most likely to have recently acquired HIV. Screening out IV drug users, men who have sex with men, sex workers, and people form countries with high rates of HIV, eliminates the vast majority of new HIV cases without eliminating a large percent of the population.
Again, people can lie so self-reporting may not be worth it. You'd have to do a study to find out. And even if it is, the number of HIV infections prevented may be so low that it doesn't justify infringing on the rights of people to donate. But, that's the debate.
[1] https://www.aids.gov/hiv-aids-basics/prevention/reduce-your-...
That being said, I've never taken a stand on the morality or efficacy of questionnaires (and I definitely don't support a lifetime ban, neither does the red cross by the way).
I do however, think that labeling a public health policy as hateful is counter productive.
Hateful implies that the doctors and policy makers who instituted the ban hate men who have sex with men (as well as IV drug users, sex workers, and people from high risk countries). I don't think that's true.
If public health is improved more by the ban, than it is reduced by decreasing the supply of blood somewhat or increasing the cost of testing, then it is totally irrational to insist the ban be removed (assuming your goal is to maximize public health).
Those aren't unrelated. They're much more likely to have HIV because of the many simultaneous partners.
Also, the testing of the blood should be better (more frequent and comprehensive, esp. HIV and hepatitis families) and not simply arbitrarily throw the few people out that actually take the time to donate blood.
EDIT: http://www.washingtonpost.com/blogs/post-partisan/wp/2014/12...
Whether an individual's rights to donate blood outweigh the risks to public health is open to debate, or whether the ban is effective is open to debate. However, the ban is driven by numbers not hate.
I tend to think the ban isn't effective simply because it relies on self reporting.
0: http://www.avert.org/hiv-aids-among-african-americans.htm
However there are a few practical differences. Banning African American's might mean less HIV infected blood, but it's not practical because African Americans make up 12% of the population, and they make up more than that for certain blood types. Furthermore banning heterosexual African Americans wouldn't reduce the amount of potentially infected blood nearly as much as banning men who have sex with men.
If men who have sex with men had similar rates of new HIV infections to African Americans and made up 12% of the population, they likely wouldn't be banned either.
If you ban men who have sex with men, you eliminate over 3/4 of newly acquired cases and only eliminate a few percent of the population.
>Because a group "might" engage in risky behavior
They don't ban people for being gay and possibly engaging in risky behavior. They ban men who have had sex with other men. This is classified as a high risk behavior (in respect to acquiring HIV).
They also ban sex workers, because engaging in sex work is defined as a high risk behavior, not because they are making a value judgment against sex workers.