There is no doubt that in Islam homosexuality is considered 'sinful'. Humans are not homosexuals by nature.
People become homosexuals because of their environments.
Particularly critical is the environment during puberty. If these conclusions are accompanied by actual homosexual acts they are even more strongly reinforced. Human instincts can be subjected to acts of will. Sexuality is a choice of identity which follows choices of action which follow from choices of what to have sexual fantasies about. Human beings are especially able to control their thoughts, entertaining some and dismissing others.