What the cultural sensitivity program was trying to get across was that the Afghan attitude towards sex was very different than in the West. Moreover, in the Islamic world sex is, well, classified, especially illicit sex. Some enterprising Western journalists have already done some reporting on the ancient practice (in the entire region, from North Africa to India) of using young (well, teenage down to about ten) boys for sex and other entertainments (dancing, cross dressing, camel jockeys). This has been a thing with the rich and powerful in the area for thousands of years. In some places it is short of legal, but generally it is tolerated, even if officially forbidden. That's because this sort of thing is most popular among the wealthy and powerful. Getting details on this story for Western audiences is dangerous, as those who indulge would rather make Western reporters disappear than just stop reporting on this topic. These guys don't consider themselves pederasts, just the custodians of ancient cultural traditions. Or something like that. Homosexuality and sex with children is particularly popular in southern Afghanistan. Abusing women (often fatally) is common throughout the country.
When the Taliban came to power in the mid-1990s, they outlawed the child sex, but it continued anyway, just more discreetly. The Taliban tried to crack down on homosexuality in general, especially in the south around Kandahar (the "capital" of the pro-Taliban Pushtun tribes). Didn't work. Casual homosexuality has long been the custom down there, and Afghans from other parts of the country (especially non-Pushtuns) have a large repertoire of humor and insults about the proclivities of those Kandaharis (one of the more printable ones is about how birds flying over Kandahar have to do so with one wing, as the other one must be used to cover the avian backside).
One of the reasons the Taliban are widely hated is because, while they officially (and loudly) condemn using boys for sex, some Taliban leaders do it anyway, as do a larger proportion of the drug lords the Taliban are allied with. Most Afghans now know that pederasty (sex with children) is reviled in the West and homosexuality is still looked down on. Given that, and the Islamic prohibitions against both practices, most Afghans would prefer if Westerners just didn’t mention it. American soldiers were advised that this was a particularly good idea if talking to Afghan soldiers or police who were armed.