Why did southern governments feel justified in passing the Black Codes?

Racist Southern whites, who had just been forced by the Union to free their slaves, enacted the Black Codes to maintain the inferior status of Blacks in the South. (Although some northern states had equally racist laws on the books.) Whites were afraid that newly-freed Blacks would compete for jobs with whites, vote whites out of political offices, and own firearms. In other Words, have the same rights as every free person in the rest of the united States. Thus the Black Codes were enacted to render Blacks inferior in employment, ownership of property, voting, and every other social and economic status that freed men could have.