Some certainly do...and some are sleepers just waiting to attack us.
The problem is, how do we tell them apart?
ALL Muslims, “American” or otherwise, are subject to “Sudden Jihadist Syndrome”, a remarkable display of blazing religious fervor marked by spraying the room with a semi-automatic or illegally obtained or converted fully automatic machine gun, shouts of “Allahu akbar!”, or the wielding of machetes or sabers used for the express purpose of decapitating the Kufir. Various explosive devices, both worn as a vest, or left resting in some public place with high foot traffic, or the use of high velocity vehicles being crashed into targets of opportunity at unexpected intervals.
And everybody is a Kufir once the jiggly little corpuscles circulating in their veins get energized.
This mental state is nourished and encouraged in the various mosques and “prayer rooms” being established in every corner of that territory once known as “the United States of America”.
If one blows you up.. shoots you.. or cuts your head off, then they're probably dangerous. /s