Couldnt Nestorius have been a really nice heretic? I mean, dont we all know really nice people in our lives who believe heretical things?
In the past, when there was a problem either politically or theologically with an erroneous practice in the Church, those who opposed it might have been in minority. They also never, ever LEFT the Church in protest, but worked and prayed within her gates. And the Truth will prevail; it always has and it always will. Those who leave the Church are removing themselves from the Body and allowing the gates of Hell to prevail against them. God help schismatics.