And what part of the United States was any of those places? Are you presuming to dictate to other countries their own domestic policies?
The vast majority of all slavery existed in Brazil. Why didn't they gather up their armies and ships and go destroy all that slavery there? It was 97% of the slavery in the world, yet nobody seems to care, because Brazil would not cost them money.
It's a fact that when the provisional constitution was presented to the convention in Montgomery one of the first objections was to the name - Confederate States of America. Attendees thought it was too limiting.
The Confederacy was 'born' with the plan to expand to points south. All the better to spread slavery.