The government says “If you’re not doing anything wrong, you shouldn’t have anything to hide.” If that is true, why can’t we know what’s in Area 51?

I give you an analogy even though it might be irrelevant or not exact replica of situation.

You are having sex with your girl friend.You are doing nothing wrong.But still people can’t know whether your girlfriend has pubic hair or not or can’t visit your pace while you are having sex.

Some things are not meant for every one. Every country has private affairs which every one must not know.

Source: The government says “If you’re not doing anything wrong, you shouldn’t have anything to hide.” If that is true, why can’t we know what’s in Area 51?