There is a small minority of people who pop up on every social media site leaving comments about Madiba being a terrorist. I'll leave you to guess the cultural background of this small group of people. For myself I get a bit tired of it and the racism that underpins this view, so here I'm going to look at this argument and expose it for what it is.
At a simplistic level (I use simplistic in the pejorative sense) Mandela was a terrorist by simple virtue of the fact that on 12 June 1964, he and two comrades were found guilty on four counts of sabotage and conspiracy to violently overthrow the government. Mandela had admitted the sabotage but denied the conspiracy to overthrow the government. The rest as they say is history and Mandela spent 27 years in Robben Island and Pollsmoor prisons.
Taken at face value and without any context being applied to the political backdrop of South Africa from the rise of the National Party's minority apartheid govt between June 1948 until democracy in 1994, then Mandela's conviction as a terrorist seems complete.
However, this is far too simplistic!