You're right of course. They should've known their place. The fact that South Africa today isn't a global economic powerhouse and social utopia proves this.
What would you do if you and the indigenous people of your country were oppressed, subjugated, disenfranchised and forced to live as 2nd class citizens. Start a petition?
Ok.
free·dom fight·er
Noun
A person who takes part in a violent struggle to achieve a political goal.
Ergo, Mandela = Freedom Fighter. No ifs, no buts. You can't say he is a terrorist, he is a freedom fighter. He fits the definition of one.