Answer:
1. To discourage support for Slave emancipation
2. To discourage the spread of ideas
Step-by-step explanation:
You did not include what country or the part of it being alluded to but seeing as this is slavery related it is most likely the Southern part of the United States.
Anti-Slavery literature being banned from the South was one of the strategies employed by the Southern states to ensure that enslaved people were not emancipated. They simply did not want the idea of free enslaved people spreading.
Humans learn a lot from others when they speak to them or hear their ideas. This leads to other people seeing things from a different point of view or being exposed to ideas they would not have thought of individually. Censorship stops this process when the people doing the censoring do not, for whatever reason, want the ideas to spread.
This is why throughout the years, there have been various censorships such as the Vatican censoring anything that could be blasphemous to God in Middle ages Europe.