Why didnt the 13, 14, 15 amendments change african americans?

The promise of these amendments was eroded by state laws and federal court decisions over the course of the 19th century. In 1876 and later, some states passed Jim Crow laws that limited the rights of African-Americans.

Jim Crow laws were state and local laws that enforced racial segregation in the Southern United States. Enacted by white Democratic-dominated state legislatures in the late nineteenth century after the Reconstruction period, these laws continued to be enforced until 1965.