Well, let's come up with a list of non-Muslim domestic terrorist organizations or other terror groups acting in the US and think of possible reasons they would attack America...
Army Of God
Church of Jesus Christ Christian
Aryan Nations
Jewish Defense League
American Nazi Party
American Third Position
Hammerskins
Blood and Honor
Black Hebrew Israelites
Republican Party (yeah I'll include them)
Tea Party (them too, brandishing rifles, spitting, swastikas and threats are forms of violent intimidation)
National Socialist Movement
Elohim City
Creativity Movement
NAAWP
Kahane Chai
World Church of the Creator
Victory Outreach
Minutemen
Maricopa County Sheriff's Department
Church of Scientology
Westboro Baptist Church (they crossed that line when one of them started sending death threats to Kevin Smith's Daughter)