Depends on what era you're talking about. Violence during Reconstruction in the South outweighed anything that happened in the North until WWI.
It was also northern industrialist vs southern industrialist and some very rich families fighting for control of even the entire nations business. The industrialized north which had built it's infrastructure on the backs of slave labor were seeing slavery as a liability for them and a threat upcoming southern industries would do likewise building up the south. So they pushed for abolishing slavery. Not out of any moral conscience but rather a business maneuver.
You need to go back to school yourself if you think that the arguments over slavery didn't relate to morality at all. Industrialists weren't the ones driving the debate. A lot of them didn't support either abolition or the war. Ordinary people with opinions played a major role in what was going on, as did preachers, teachers, and journalists.
Slavery had become as much a liability in the north due to cost of upkeep vs automation as a mule to a tractor today. Or as Surface Mining with a smaller crew or a Deep Mine with a large crew. Ever hear of Coal Wars? How about the Coal Creek War which happened long after the Civil War. The late singer Tennessee Ernie Ford sang a song about the realities of a miner called Sixteen Tons. "St Peter dontcha call me cause I can't go, I owe my soul to the company store." Company owned the store, houses, the land, and by low wages vs prices charged in the company store vs paid wages always kept them in debt. It was a time when if you owed money and didn't pay you could be arrested, your possessions sold, and if you were lucky you and family sent to The Poor Farm.
Post Civil War was not good for blacks in the north or the south. Poverty and jobs no one else would do for the wages awaited them. Yeah the north had a heaping helping of morality LOL.
BTW a person could then and still can now understand the Confederate side of the argument of States Rights to self govern, and support it, and still personally be against slavery.
Slavery is stil and has been GOD's refining tool used throughout the history of man for many reasons including a judgement, an adversity given to overcome the adversity by becoming GOD dependent rising up from it, and to even save nations. Read about Israels {Jacob's} son Joseph.
The Bible does not prohibit slavery. In previous times it was an economic necessity. It does however specify the conduct expected of both owner and slave and it is strict but I doubt a few of the Reverends who stir up racial discord amongst Americans have read it. Personally I would never want such responsibility as a slave.
Now to the morality of it all. Men fled the crown and came to The New World in search of freedom to worship GOD as they saw fit. Persecution was common in Europe to those who did not submit to the crowns choice of church such as it was. Eventually a group of men would write the document called The Declaration of Independence and lead colonist into The Revolutionary War to break away from Britain. Their morality for some including owning slaves including one Thomas Jefferson and first POTUS George Washington. GOD Blessed the USA and the Founding Fathers because men sought to abide in His Word. GOD Blessed their efforts and they succeeded.
Slavery? Let's discuss it here a few minutes in a light many never talk about. Slavery brought The Word Of GOD to the slaves. It brought education. Morality? They worked six days a week and attended church from sun up till sundown Sunday evening. This tradition still existed in many predominately black churches likely even into the 1960's.
Which destroyed them? Better still which destroyed this nation? Slavery and relying on GOD for deliverance? Or LBJ's Great Society which replaced GOD, Church, and Family? No not just to the blacks but the white population as well. Both white and blacks came to this nation and many in both races were as such slaves. The whites to the Crown or debt holders the blacks the same then to their owners after the revolution.
BTW what race has been enslaved for the longest in the history of mankind? The most attacked through out recorded history? The most persecuted? That race still faces such today and you'll have to look hard in the media too find and news about it except to make that race as one who always is at fault in the eyes of the world governments just as The Bible has predicted, the media, and our current POTUS. That race BTW contributed a substantial amount of funding to fund the Revolutionary War. One man to be specific died broke because the new U.S. government did not repay it's war debt. He was a man Washington knew as well as Madison. It was a man who helped arrange for a large amount of the money needed to buy this nations freedom and fund the Continental Army. I bet you most professors of history teaching post WW2 revisionist history can't name the man. Can you? :>} He doesn't appear in public school history books either as far as I know. Yet his race from Egypt to the Roman Empire, to the USA either in labor or later funding in the case of the USA built great nations.
Yeah it is one race the poverty pimps pushing racial division like to use blame on their races woes on.
Morality? Hum we ignore The Bible and today our elected leaders join in a persecution of a nation and race which history says time and time again leads to the fall of those who attack that people.
Today our nations is in a downward spiral. A cultural revolution began by Marxist back in the 1930's started it. That revolution has destroyed black and white families as well as morality once held by both. It has inflicted far more damage morality and lives lost than the The Civil War did in terms of death of innocents as well and lowered national morality. But the Confederate Flag is the enemy? Yes so sayeth the Marxist Professors and their gullible sheep and a few rich race baiting reverends making massive fortunes off of it. What race do they hate most? Think long and hard on that one.
The Republican Party was born as a Liberal Party few realize that about it and it has returned to it's roots as such. It was born of a party of strong central government literally overseeing what until that time had been states sovereign rights and powers. Honest Abe shredded the Constitution of the USA and set the course for Socialist like FDR, LBJ, and finally Obama, to lead this nation into it's days of self destruction.
Slavery would have died probably sooner and with less damage and harm to all by simply allowing the economics of it to make it profitable and a liability. Honest Abe in a hurry to appease economic factions caused a disaster for all.
POTUS Elections have been brokered by very rich men's money since the 1860's with a few exceptions. We're losing the war of morality but it isn't a black and white issue except in the sense we as a nation have chose to ignore the black & red typed words placed on white sheets of paper we call The Bible and let government dictate new morality just as the Marxist in power of it now dictate. You think all the attention to the Confederate Flag is driven by blacks? No! Who is beating it into their heads over and over that they are victims? We as a nation don't hear about black preachers and black politicians pushing for personal responsibility and a return to morals. They are called Uncle Toms. We instead hear the ones who for personal profit joined the side of Cultural Marxism destroying this nation. If the US returned to the standards of Morality of the early 1800's we would not be in this huge mess we are in.