Merrick Garland

No, but there are white Christian conservatives who are domestic terrorists

But they didn't want certain other groups to be labeled "domestic terrorists" instead of by their religion, as if that made them perpetual foreigners.

Correct.
'White' Christian Conservatives got so irritated with the notion of calling any domestic Islamic terrorists, "domestic terrorists," that they thus in effect reserved the label solely for themselves, given the dearth of anyone else engaged in domestic terrorism.