Here is the structure the South African government used.here are the crimes committed by the South African terrorists.

Nearly all Catholic Church saint stories start out with the saint being a sinner, doing some bad stuff. Because they know this is a good hook! To make them seem like real humans!

The NYTimes obit does use the word terrorism for that period in his life and for the ANC, here's full enough excerpt to get the nuance:

[....] Mr. Mandela’s exploits in the “armed struggle” have been somewhat mythologized. During his months as a cloak-and-dagger outlaw, the press christened him “the Black Pimpernel.” But while he trained for guerrilla fighting and sought weapons for Spear of the Nation, he saw no combat. The A.N.C.’s armed activities were mostly confined to planting land mines, blowing up electrical stations and committing occasional acts of terrorism against civilians.

After the first free elections in South Africa, Spear of the Nation’s reputation was stained by admissions of human rights abuses in its training camps, though no evidence emerged that Mr. Mandela was complicit in them.

During Trial, a Legend Grows

South Africa’s rulers were determined to put Mr. Mandela and his comrades out of action. In 1956, he and scores of other dissidents were arrested on charges of treason. The state botched the prosecution, and after the acquittal Mr. Mandela went underground. Upon his capture he was charged with inciting a strike and leaving the country without a passport. His legend grew when, on the first day of that trial, he entered the courtroom wearing a traditional Xhosa leopard-skin cape to underscore that he was an African entering a white man’s jurisdiction.

That trial resulted in a three-year sentence, but it was just a warm-up for the main event. Next Mr. Mandela and eight other A.N.C. leaders were charged with sabotage and conspiracy to overthrow the state — capital crimes. It was called the Rivonia trial, for the name of the farm where the defendants had conspired and where a trove of incriminating documents was found — many in Mr. Mandela’s handwriting — outlining and justifying a violent campaign to bring down the regime.

At Mr. Mandela’s suggestion, the defendants, certain of conviction, set out to turn the trial into a moral drama that would vindicate them in the court of world opinion. They admitted that they had organized a liberation army and had engaged in sabotage and tried to lay out a political justification for these acts. Among themselves, they agreed that even if sentenced to hang, they would refuse on principle to appeal.

The four-hour speech with which Mr. Mandela opened the defense’s case was one of the most eloquent of his life, and — in the view of his authorized biographer, Anthony Sampson — it established him as the leader not only of the A.N.C. but also of the international movement against apartheid.

Mr. Mandela described his personal evolution from the temptations of black nationalism to the politics of multiracialism. He acknowledged that he was the commander of Spear of the Nation, but asserted that he had turned to violence only after nonviolent resistance had been foreclosed. He conceded that he had made alliances with Communists — a powerful current in the prosecution case in those Cold War days — but likened this to Churchill’s cooperation with Stalin against Hitler.

He finished with a coda of his convictions that would endure as an oratorical highlight of South African history.

“I have fought against white domination, and I have fought against black domination,” he told the court. “I have cherished the ideal of a democratic and free society in which all persons will live together in harmony and with equal opportunities. It is an ideal for which I hope to live for and to see realized. But my lord, if it needs be, it is an ideal for which I am prepared to die.”

Under considerable pressure from liberals at home and abroad, including a nearly unanimous vote of the United Nations General Assembly, to spare the defendants, the judge acquitted one and sentenced Mr. Mandela and the others to life in prison.

An Education in Prison [....]

Is that kind of nuance okay with you, where the person did some bad thinking and learned from that, or must he be presented as a saint for every minute of his life, for  him to work as an icon and inspiration?