Why did Southern states begin passing Jim Crow laws when Reconstruction ended?

Southern states began to pass Jim Crow laws after Reconstruction because that was the only way to ensure the freed slaves wouldn't impact or alter Southern society in spite of their rights under the 14th Amendment. Prior to Reconstruction, slavery served the dual purpose of supporting the Southern economy and reinforcing the concept of white supremacy. However, following the Civil War, slavery was made illegal and Reconstruction laws also made it difficult for racist politicians to purport the idea of white supremacy in law (for example, a number of freed slaves served as Senators and Representatives during Reconstruction). However, once Reconstruction had ended, white politicians created voter suppression tools such as poll taxes and literacy tests to reduce the number of African-Americans who could vote. Additionally, this was the period in which Southern states adopted segregation laws to keep white and African-Americans separate.