http://www.salon.com/news/feature/2009/04/16/tea_party/
The type of person who wants to keep their guns isn't the kind of person that the government is worried about.
The government is worried about the kind of guy who wishes that Flight 93 had hit its target on 9/11 (see the article). They're worried about the kind of person who can't tolerate having a black President. They're worried about the kind of person who thinks that Hitler wasn't half bad. They're worried about the sorts of people who want to use the skills they acquired to defend this country to do harm to it. They're worried about the kind of people who think that they'll help this country by killing hundreds of innocent people by blowing up a federal office building in the middle of the country.
Domestic terrorism is a real threat, from both the left and the right. It's wrong to think that somebody can't be a terrorist just because they're form the same part of the political spectrum as you.