The Freedmen’s Bureau was created in 1865 during the Congress Reconstruction and it aimed to help African Americans following the Civil War and the achievement of freedom. The Bureau provided food, housing, medical aid, offered legal assistance and helped African Americans to protect their civil rights such as vote.
A public service is the task of proving service to a community or the citizens of a country. It includes all enterprises of public welfare and development.
The service rendered to military is an example of public service as military/army comes under the domain of public or governmental authority.
Therefore, serving in a military is similar to serving the public as it protects the people from internal or external challenges and unrest.