I work on HIV/AIDS epidemiology, so I have read many, many studies on behaviour and risk with regards to sex. The main reason pretty much always given in every study for not using condoms are what pretty much everyone has already said - caught up in the moment, alcohol or drug use, fear of rejection, powerless to make the partner wear a condom, and so on. Education does play a part, as less educated people tend to have lower rates of condom use. See the VIDUS study, Vanguard, OMEGA, the St. Luc Cohort, the San Francisco Young Men’s Study (can’t remember if that’s the exact name), and countless others. The biggest reasons among gay men seem to be alcohol and drug use, and among young people seem to be having no fear.
To those who have stated that HIV is not the death sentence it once was, I imagine you didn’t mean at all, but nonetheless this attitude is what is hurting mostly young gay men in western countries (not Africa or southeast Asia, anyway). A lot of these men were born when the disease started, and thus never watched their friends and loved ones die of AIDS. Ask a gay man in his 40s or older, and I guarantee they’ll know someone who died of AIDS. The fear is not there anymore, and some studies are showing increases in risk behaviours among young gay men (Vanguard, in Vancouver in particular) that are causing higher incidence rates (how many people are contracting a disease) than in previous years.
Part of the difficulty is the belief that antiretrovirals are always there just in case. Problem is, though they prolong life, they do not eliminate the infection. I read two separate studies (can’t remember the exact cites) where the estimate for survival on ARTs is between 16 and 25 years from contraction of HIV, while it used to be 8 to 10 years. Better, but not best. And ARTs are very, very harsh. They are toxic, can have serious negative side effects, and are generally not desireable except in extreme circumstances (like after you find out you’re HIV positive).
That said, there is still no good reason to avoid safe sex practices. Unless you know your partner’s history, you’re a fool not to. Go to the CDC’s website and sign up for the Prevention News on the HIV web section. You’ll get an email every day detailing increased rates of chlamydia, gonorrhea, syphilis, and other STDs, mainly among young people (and for some reason mostly in the US South), as well as much HIV news. None of these things are easily cured. They can be cured, but it isn’t nearly as simple as unwrapping a condom and rolling it on. There’s really no good excuse.
Malacandra, you mentioned a higher prevalence of heterosexual anal intercourse in sub-Saharan Africa, and you may be on to something. Researchers are looking into it, because they do believe it to be an issue, as anal intercourse is more risky. There is a very strong belief from what limited research has been done that anal intercourse is more common in sub-Saharan Africa than elsewhere. We’ll have to wait and see. There is also a very large problem with the role of women and how they are valued in society. Women are often powerless to get a man to wear a condom, and sub-Saharan African men are generally taught to be macho and dominant, and refuse. There is plenty of research on this, easily searched for.