That said, I think the Red Cross is just being responsible and looking at the issue objectively. One group has a significantly higher occurrence of HIV than another, so in the interests of the patients, it's probably best to exclude, or at least restrict, that group.
Hmm... Let me rephrase this in a different context.
The black community has a significantly higher occurrence of being imprisoned than another, so to the interest of society, it's probably best to exclude, or at least restrict, that group.
1) In the interest of the patients, to keep them safe, we should exclude gays from giving blood. Well... the same argument can be made to protect society from blacks. Not only is the original text in red wrong, but it's borderline racist.
2) Like other people have said, straight people can give blood when they don't even know if they are carrying any STIs just because they don't check a single box...
The only objectives the Red Cross is trying to pursue are apathy and ignorance.