The issue isn’t whether people thought slavery was wrong - the consensus seems to be that in the non-slave states, the majority of people disliked the institution in the abstract. That doesn’t mean that they were willing to see the nation torn apart and have hundreds of thousands of their countrymen die in order to end slavery.
No, but southern fire eaters were willing to tear the nation apart to protect slavery. Luckily there were enough loyal Americans, both north and south, to insure this didn’t happen.
One of my favorites is Rear Admiral Samuel Phillips Lee, cousin of Robert E. Lee. When he was asked about his loyalties during the secession winter he stated, “When I find the word Virginia in my Commission I will join the Confederacy.”