The abolitionist Garrison was chained and paraded in the streets. Prudence Crandall's school for black girls was attacked. The KKK had a tremendous presence in Indiana. There were race riots in the North when Black Southerners moved North in search of jobs in industry during the World Wars. The number of states allowing adult, Black males to vote actually declined as the Civil War approached. Racism was endemic. It only varied by degree and how open it was.
What you see in that picture exactly happened in the North too. Gosh George Carlin was right, some people are really stupid. There was no subliminal or closet racism in the North. The hatred was open in the North too. When blacks came to Northern cities in the 1930s, they were in for rioting by white racists.
Racism certainly existed even in the free North. For example, blacks were denied the right to vote. Black people were not allowed to live in the same neighborhoods as white people, so there was open segregation. It could also be far more difficult for them to find jobs. Just because the North was free didn't mean that white people didn't still have unfair prejudice against them.