Umkhonto we Sizwe did go to hell after he was imprisoned and become a terrorist organization, but it's hard to blame someone locked up in prison for that. I don't see any standard by which you could claim Mandela was a terrorist, which wouldn't also sweep up some of America's founders.

Mandela was no Gandhi, no saint. He resorted to discriminate violence when otherwise thwarted in fighting against injustice. But given them sum of his life I would aspire to be as humane a person as he was.