Answer:
In the text, we can see how Nelson Mandela contrasts a primitive form of freedom that he enjoyed when he was young: the freedom to run around as a kid, and do as you please as long as you obey your fathers, to the freedom of reaching your full potential, as an adult man.
And it is the latter form of freedom that he could not enjoy because he was black, and black people in South Africa, at the time, had many restrictions and were treated worse than White People.
Mandela explains that it was this kind of freedom that he lacked, and it was this lacking that pushed him to become a revolutionary, with all the negative consequences that such decision had to his personal life (spending decade in jail, away from his family, being in danger, etc).
