Freedom means being able to choose how we respond to things. When wisdom is not well developed, it can be easily obscured by the provocations of others. In such cases we may as well be animals or robots.
If there is no space between an insulting stimulus and its immediate conditioned response—anger—then we are in fact under the control of others. Mindfulness opens up such a space, and when wisdom is there to fill it one is capable of responding with forbearance.
It’s not that anger is repressed; anger never arises in the first place.