It can mean that you can get what you want easier when you're being nice.
To me it means as a sign for inspiration and honor, and i believe the way the quote was intended to portray is-- Without America fighting for their freedom, risking everything and every life, they wouldn't have been known as people who took a stand and fought for what they deserved. It stands in history as monument to everyone around the world that freedom is always hard fought, but without the courage and the strength to truly want what you feel you deserve and therefore earned....be prepared to lose everything.
Answer:
For fear of retaliation against them.
Explanation:
Douglas wouldn't want fot the boys who taught him how to read to get in trouble on his behalf. He was afraid that they would be repremended or punished for having taught him how to read.