For the purpose of this post, let's stipulate that most northerners knew human bondage was morally wrong and that, in their hearts of good intentions, they really wanted to stop profiting from America's guest worker program.
If true, that would make the decision of northern states to vote to unambiguously include slavery in the U. S. constitution all the more appalling.
Appalling that Northerners were willing to sacrifice their abolitionist principles to achieve national unity?
Appalling that Northerners considered their Union more important that abolition?
Appalling that Northerners were willing to delay by generations the South's "come to Jesus" on slavery moment?
Sure, appalling to committed slaveholders, not so much to any others.