It's not that anything is patently false, but like most public health information derived from statistical studies, discourse about HIV, hepatitis, etc. is fairly euphemistic. For example, good caseworkers frequently treat all unprotected sex as of the same order of risk--so they wind up telling people that oral sex is an immanent life-risk and that they should use condoms for oral sex--with men. For 98% of the gay men I know, oral sex with a condom might as well be oral sex with a cucumber or a dildo. That is--it's not sex at all, even though it can get you off. Two opposing responses to this are common: 1. paranoia about any sexual contact (seen very often); 2. a sense of hopelessness that safe sex could ever be satisfying or intimate--and so a total disregard for any precaution whatsoever (seen less regularly, b/c such people wind up in barebacking and unsafe sex subcultures).
I don't really have a solution to this--in a way, public health discourse _should_ be conservative. But I do wonder if it isn't possible to explain exactly what the risks are and aren't. Although it is _possible_ to be infected by having sex with one HIV+ person, so many things have to happen in just the right way--their viral load has to be a certain level, the body fluid has to get to your blood stream in a certain amount of time, your immune system might have to be compromised--that it almost never happens if you are exposed to the virus only once. I mean, even if you have unprotected anal sex with a positive partner (and you're the bottom), your chance of actually being infected is about 1%. That's if your partner is infected and you're doing the highest risk sexual activity we know of.
Although it's totally un-PC to say so, it's not about _what_ you do--that is just the easiest thing to control. It has more to do with who you do it with, how often, under what circumstances, etc. It is about "lifestyle" choices, in other words--and you have to wonder if there isn't a better way to "have promiscuity in a pandemic," as Leo Bersani (I think) once put it.
Christian