Maybe true, but don't lose sight of the fact that "Unitarians, Presbyterians, Quakers, Baptists, Episcopalians, Jews, Shakers" all come from the same tradition/

Maybe true, but don't lose sight of the fact that "Unitarians, Presbyterians, Quakers, Baptists, Episcopalians, Jews, Shakers" all come from the same tradition/belief/value family tree, as it were. They were all once tight communities "homogeneous in traditions, beliefs, values, etc." that eventually split (though perhaps they weren't still "tight" communities by the time of those splits). In any case, people are good at finding things to disagree about--and groups of people in elective association are good at fracturing over disagreements.