Answer: The Northern states held mixed views on slavery.
Explanation: The abolitionists opposed slavery and its expansion while some others only sought to limit slavery to the South. Some of the workers in the North who feared that freed slaves might move north to claim their jobs also supported the continuation of slavery. A lot of northern business owners also favored slavery because they profited from it.
However, even those who were not abolitionists opposed the Fugitive Slave Act (which required that all escaped slaves, upon capture, be returned to their masters and that officials and citizens of free states had to cooperate) because the law required them to support slavery. Many Northerners simply refused to comply with the law while others continued to help shelter and transport escaped slaves on the Underground Railroad.
The one that is incorrect is this one: The massacre began because of a violent outburst by protesters towards passerby that supported the current government. Simply opposing the regime was a crime in their eyes, and thus the massacre happened.
