I really don't understand the post-security water issue. I got in an argument with a security person at the Hong Kong airport over this. They claimed it's a req

I really don't understand the post-security water issue. I got in an argument with a security person at the Hong Kong airport over this. They claimed it's a requirement by the US government and showed me some document that described rules similar to what we see in the US. So I argued that they are reading the document wrong and got rather worked up till my wife started to pull me away because she was afraid I would get arrested.