Answer:
The freedmens bureau closed in 1872 because
The congress didn't approve renewal authorizing legislation.
Step-by-step explanation:
The freedmen's bureau was closed in 1872 after the congress didn't approve renewal for it. But it happened after the democrats took out half of its funding and the Ku Klux klan attacked their supporters as well as collaborators, and beneficiaries. Furthermore, disputes between the last Bureau leader Howard and the current secretary of war influenced the controversy around it.