Why could African Americans not vote after The Reconstruction Poll taxes and literacy tests?

The 13th Amendment to the Constitution ended slavery- but that's all it did. Slaves were considered property- they were owned, just like you own a car, a house, or a chair. They were rarely ever taught how to read or write, and because they were owned, they generally didn't own anything.

So then, on December 18th, 1865, slavery was abolished by the 13th Amendment. These people who previously had nothing were suddenly free. They still had nothing and still couldn't read or write. So poll taxes and literacy tests were easy ways to prevent these newly freed black people from voting.