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.