U.S. culture is culture of taboos. There are things, that you cannot talk about, and expect people to react in an adult way. You cannot really talk about your sex with your parents, as a teenager, and expect a proportionate and caring response; any stupid thing you do can result in community-wide moral hysteria. There is alot of repressed sexually, which either results in excessive prudery, or disproportionate out lashes. Because sex is sinful, according to the church. Did you see the way americans freaked out when janet jackson titty popped out at the superbowl??? That would never happen in Nepal, Cambodia, Vietnam and European countries like Spain, Sweden, CR or anything other country you could name
U.S. Americans are prudish, because they are terrified of their own sexuality, due to the unhealthy attitude of Christianity, that is mostly gone in Europe by this time. ironically, often rightly so, because such repression can often foster unhealthy tendencies.