You get a bonus of two answers:
I'm not Df'd, and I'm leaving as a stand for the survival of the world - against religious fundamentalism, pessimism, and intolerance.
However, Df'ing does not work as anything other than a fear to keep people in the organization who don't really want to be there. Df'ing a 'repentant' person does nothing but damage them emotionally. Df'ing an unrepentant person does nothing - for them. It promotes unity (i.e. control) in the congregation.
This world needs community, not control; leadership, not power; growth, not fear.