Answer:
In the quote you provided, Douglass is referring to the way that slave owners in the United States used various tactics to prevent enslaved people from wanting to gain their freedom. One of these tactics was to allow enslaved people to see only the negative aspects of freedom, such as the abuse and mistreatment of freed slaves, in order to discourage them from wanting to be free themselves.
By presenting freedom in this way, slave owners hoped to prevent enslaved people from aspiring to gain their own freedom and to discourage them from seeking to escape or rebel against the system of slavery. Douglass was critical of this tactic and argued that it was used to maintain the system of slavery by undermining the desire of enslaved people for freedom.