Muslim extremists are rare. The majority of assholes that go apeshit murdering are white non-muslims. There even isn't any evidence hasan did this because of islam but hell, we all know the islamophobic camps have already set up shop to deride islam out of their ignorance and hate.
"Rare", I believe I can read about a muslims killing people every single week. They bomb tourist attractions, commuter trains, government buildings, neighbors, strangers, other sects, and other religions. Are you telling me those are normal, religious muslims and not extremists? Muslim extremists are becoming very common. They work the same way other hate groups do (that can be against race, religion, sex or any other reason); they go to people that are unable or afraid to do anything for themselves and tell them for a small fee, they will hate the 'select' group for them. Once the funds are coming in, the leaders recruit LOSERS to action; they promise them recognition and glory (remember to these losers, it is all about them and the power they have to influence the world), in exchange for martyrdom. Unfortunately, this system works quite well and is now being employed by our gov, the losers: the congress, the victims: the taxpayers. Sorry, I digress, terrorists that are of muslim faith can be found every week, in almost every country in the world. Only fools will not recognize this, and in doing so will empower the terrorists to expand and recruit, hurting not only this country, but muslims that suffer at the terrorists' actions as well.
Will you give the terrorists power by pretending they don't exist and can't hurt anyone, or will you confront evil, and tell it, there is no welcome for actions of that type in today's world?