It would be the "Ku Klux Klan" that is considered to be a domestic terrorist group, since they have a long history of intimidating people (especially blacks and Jews) with whom they disagree and degrade.
B. If you're referring to the Abrahamic Covenant (circumcise your kids because all Jews are Abram's grandkids) then yes. Christians don't acknowledge this, and anyone can enter Christianity through the sacraments.
