Well, Britain ended slavery decades before we did and it didn’t cost 700,000 lives
England was pro slavery during the colonial years and up past the revelation.
Christian colonialist tried to get England to outlaw slavery, because they saw it as appauling. The King refused, because the crown’s plantations needed the slave labor.
Fact, look it up.
They abolished it many years after the Revolution was over. Yet they still shipped slaves all over the World. Who do you think was supplying the slaves to the United States? It was England with the approval of the British Government.
Study history.
then dedicated a portion of the Royal Navy to the mission of ending the trans-Atlantic slave trade between West Africa and the Americas.