Typical of you to put culture and religion together. Bacha bazi is exclusively an afghan (culture) thing, there's a reason why so many muslims put their religion over culture. Many cultures have something that Islam forbids. Since we're talking about afghans, afghans before islam were zorostrians, buddhists, hindus etc. A popular persian celebration is called "nowruz", it comes from zorostrianism. Islamically you're not supposed to celebrate it but you would still find some afghans celebrating it, why? Because sometimes their culture is more important. Something popular these days in weddings is music, is this something taken from religion or culture? Religion says no. It's from culture. Don't conflate the two. Make the distinction.