What happened at Sharpeville wasn't nice either, and did much to turn Mandela away from non-violence.
He could have said to those who imprisoned him, "You made me this way," and left it at that, but he did much to remake himself yet again, this time turning away from the ideas of his more radical and violent associates.
You really can’t go very far “remaking” yourself without reference to God.
Tutu may have been a help here, to be fair.