It's surprising because the government doesn't exactly talk about it a lot. Thus, most people who don't follow security issues don't hear about it very often. It's not like the government advertises these activities with billboards and TV spots. The reason they don't is because this broad interpretation of their responsibilities makes them look pretty bad without having a long discussion with a lot of context. As it is, people might just ask them to stop reading their emails. So, if the people doing it don't talk about it, why would you be surprised that other people don't know it's happening? It sounds like you're saying "I'm surprised that not everybody pays careful attention to the specific domains I pay attention to", but remember that it takes all kinds of people to make the world go round.