While I was in a boarding school, I knew several guys at school who actually had anal sex with other guys but they never thought of it as “gay” because there was no such concept. They think of it as the next best thing to a vaginal sex but better than masturbation. I think this mindset is common in most developing countries, especially their youth. Almost all of these people get married and often have satisfactory sexual life. I do think majority of those guys are straight.
I think it has lot to do with the culture of those countries. Often I hear of surprised Westerners talk about seeing guys holding hands in public in Middle East and other conservative countries. Unlike in the west where straight guys are often cautious of not doing anything that might be perceived as “gay”, most other cultures just don’t have this issue. I am not saying these cultures are accepting of gay in their community, in fact it is the opposite. Most of these countries are so intolerant that almost all LGBT remain closeted. These countries also lack sexual education and talking about sex is a taboo. So I think it is reasonably possible that if LGBT rights do come into national conversation in those countries, you will see lot fewer straight guys holding hands in those countries.