These are listed as some of the main reasons as to why the Fugitive Slave Act created division between the North and South:
The North was industry-based and relied more on the urban lifestyle; whereas, in the South, the industry was slave labor. Thus, being that Southerners felt that slaves were lazy and/or incompetent they wanted, through the law, to control the movements of runaway slaves by returning them to the plantations. This was even more controversial as free, Black men were re-enslaved and used for cheap labor. This led to a rise in abolition efforts and the ways that bounties and harsher punishments were given across the nation.