My life at my former company began as a temporary worker who picked up the slack during the annual busy season between November and March. There were 4 full-timers and 5 of us temps. The full-time workers were John, Jolene, Doug, and my former boss Darryl. Doug and Jolene were both married but John was single. I sat in a cubicle next to John so I got to know him first and best.
Even though I'd been in Japan for two years at that point, I had limited experience with the types of gaijin Lotharios who treat the local women as potential harem girls for their sexual entertainment. To those who don't know, there is an unflattering but sometimes accurate image of some western men who come to Japan for the potential to score and are able to romance women largely based on the fact that they are foreign. These are typically the kind of men who couldn't get women back home for one reason or another and who like to carry on about how western women are inferior girlfriends/wives compared to Asian women. I guess it's easier to say you don't want something because there's something wrong with it than to say you can't have it because there's something wrong with you.
Before all the nice and well-adjusted men who have Japanese girlfriends/wives initiate their hackle-raising maneuvers, I'm not talking about you. Note the use of the word "some (western men)", not "all". Well, maybe I am talking about you if your dander is fluffing at the mention of this topic. If the very notion that there are some predatory foreign men out there who are losers who can attract Japanese women because the culture and communication gaps mask their more repugnant character attributes then you may be one of them. Otherwise, why would you get all worked up about it? If it doesn't bother you then you likely aren't one of them and are confident in your appeal to the opposite sex in any culture.
Anyway, John was my first experience face-to-face with one of these types of foreign men. Previously, I'd associated with men who were pretty decent (mainly married to Japanese or foreign women already, gay, or plain decent fellows who were open to women they encounter but not hunting them down as sexual trophies). He would come in some days looking like he'd slept in the clothes he wore the day before because he actually had done so. He slept with any girl he could and, since he looked like a pint-sized Bruce Willis, he didn't seem to have too many problems locating some accepting women who didn't mind a guy on the short side. He didn't respect Japanese women at all and in fact sometimes called them "honey" when he was teaching them on the phone as a sort of snide joke. His attitude toward them was as something he could use for sexual pleasure.
At some point, John, Doug, and I were having a conversation about John's dating habits and, of course, he wasn't shy about talking about how many girls he'd slept with in Japan. I can't recall the precise number but it was not some ridiculously small or large one. The topic of birth control came up and John said that he never wore a condom. When Doug and I expressed that we strongly felt this was very dangerous, particularly from a disease point of view, John said, "I only sleep with nice, clean girls."
Doug and I tried to convince him that STDs don't distinguish "clean" from "dirty" but he had no plans to start wearing his raincoat when he went splashing in the rain with his "clean" playmates because he was certain they wouldn't splatter any mud on him. Unfortunately, his attitude is not uncommon among either Japanese or foreign people who feel that Japanese people, and the women in particular, are too "clean" to carry or transmit STDs. This was a fact that I was reminded of when I read an unhappy story on Stippy related to this topic (which I recommend others read as well).
The irony is that many foreigners are aware that Japanese businessmen frequent the sex trade in Thailand and other Asian countries they pass through. While I'm sure most of them wear condoms, some of them do not and they are still at risk of contracting STDs from visiting prostitutes. If the knowing gaijin puts two and two together, he'll realize that it's only a matter of time before such men return and infect unsuspecting women and diseases will start making the rounds.
The fact of the matter is that HIV and AIDS are viewed as "foreign diseases" and doctors will lie to patients about their diagnoses if they feel the truth is going to be too hard on the patient. The shame associated with dying of AIDS as a cause of death may result in the cause of death being listed as the disease that the person succumbed to as a result of his suppressed immune system rather than as a death because of AIDS. This misleads people about infection rates and the possible risks that come from having unprotected sex and continues to contribute to the myth that Japanese people are, by and large, too "clean" to spread (potentially fatal) STDs.
Update: There's a thoughtful article on AIDS on Stippy which analyzes statistics in Japan which everyone should read as well.