"Civil disobedience" by Thoreau is mainly purposed towards citizens, and how they should be willing to act on there opinions.
"If the machine of government is of such a nature that it requires you to be the agent of injustice to another, then, I say, break the law."
Thoreau truly believed in speaking your mind. Just like Rosa Parks did, and Martin Luther King Jr. An agent of injustice would be a product of a person that does not want to be different.

Civil disobedience - Thoreau