I have read books by (former) soldiers who were in Afghanistan. They described homosexuality in Afghanistan as sort of like prison sex. That is, men and women are so segregated and often married men are away from their wives for long periods that homosexuality is seen as a release of biological urges rather than a particular "lifestyle" or choice...it is simply a means of continuing human sexuality by other means than the most socially accepted way. Although, the descriptions of the acts and others' reactions to it gave me the impression that it was more highly accepted by Afghans than by Americans. Such as one soldier describing the first time he witnessed it, a few Afghan men were on break from the work project this American was supervising; two Afghan men went over behind a tree and began having sex and the American broke them up threatening them with his rifle. The other Afghan men simply sat around and smoked, ate lunch, talked, and laughed when the tryst was broken up.
A man I know who actually went there said that pederasty was common. He and others at the free care clinic he was assigned to called it "Good Friday, Bad Saturday." He said that every Friday (the Islamic Sabbath) after the main prayers were over, young boys would be dressed as effeminately or androgynously as possible then the older men would have sex with them. That was Good Friday; the next morning or Bad Saturday was when all the mothers of these young boys (he said they Afghan men made a point to pick pre-pubescent or slightly pubescent boys since they appeared more feminine to begin with and had no facial hair) would bring them into his clinic for treatment. He said it was horrible, they were treated of course for the physical signs of repeated anal rape and that they cried, feared the touch of men like the doctors or nurses, or seemed catatonic like someone who had run out of tears to cry anymore. He explained that this was a weekly occurrence and some of the same boys were seen repeatedly so it seemed like the whole village was aware of it and nothing was done to stop it. He also said that the fathers never came which lead him to believe that they probably participated in it even if not with their own children but allowed theirs to be raped so that they may rape another's children. Horrible, he said that bothered him more than anything else over there and also made him realize that he was fighting to maintain a horrible status quo. He got out after that tour in Afghanistan.
Also, the Afghans use sodomy as a control tool, like in American prisons, to humiliate their enemies. One reason Russian soldiers began carrying grenades to kill themselves with during the Afghan-USSR war was that soldiers taken alive were subjected to gang rape and being held, for as long as they lived considering the abuse and starvation they would face, as "war brides" of the Afghans who captured them. The CIA in the 80's even got photos of makeshift brothels which were nothing more than captured Russian soldiers held bent over in a sort of pillory with dozens of Afghan men lined up behind whichever one they chose to take their turn. The CIA of course did not get too outraged at this but when they found out that some of the prized pack-mules donated by US breeders to help the Afghans were also being used in the same way as were the Russian captives, then the CIA threatened to not send the mujahideen anymore mules.
So, in Afghanistan being "gay" is not as easy to pin down as in the West. Though to us, at least to me, gay sex seems fairly prevalent. Even if you could not call the cultural attachments to it an umbrella social phenomenon like we would call being gay or homosexuality as a cultural identity it seems that they accept it so long as it is simply isolated actions that are kept apart from "normal" sexual behavior. But I also suspect that this type of behavior continues out of the "victim becomes victimizer" mentality.
"Better a cruel truth than a comfortable delusion." - Edward Abbey