I do not have the 2nd amendment right in front of me but from my memory it does give an individual the right to form and independent militia. In order to protect America from invaders, both foreign and domestic, it gives Americans the right to for an independent militia. This is in the case that the government has turned bad and needs to be overthrown.
It depends on what the persons intent is. I feel as though you should feel safe in the United States based on the power of our army. The only reason you would have an independent militia in the United States is because you have something against our own government or you feel unsafe in our country.