Many abolitionists and anti-slavery activists viewed the colonization plan as a compromise that fell short of their ultimate goal of complete racial equality and the end of slavery. They argued that the colonization plan would perpetuate the idea that Blacks were inferior and unable to live alongside whites in the United States.
Some anti-slavery leaders also believed that the colonization plan was impractical and would be difficult to implement, as many Blacks were not willing to leave the United States and would resist any attempts to force them to do so.
Additionally, some anti-slavery activists felt that the colonization plan was a way for the government to avoid addressing the underlying issues of slavery and racial discrimination within the United States, and instead focus on removing Black people from the country, which they saw as an unjust solution.
Overall, the reaction of anti-slavery people in the North to President Lincoln's plan for the colonization of freed Blacks was one of disappointment and opposition.