I think one of the biggest problems is that parents still associate homosexuality with paedophelia. Since the BSA is a children's organisation, even "well-meaning" parents see it as just one more risk factor that can be easily eliminated by excluding a group of people. It's a false sense of security rooted in a lack of education and lifetimes of media sensationalism and organisational corruption. (Personally, I wish the BSA and the GSA would join forces and end exclusivity based on orientation or gender altogether. I do not see the value in dividing the sexes.)