I am too lazy to research but other than Abraham Lincoln, how come no presidents before him ended slavery?

Mainly due to the social norms of the time but another reason why Abraham did free the slaves unlike any others was the fact of industrialization in the North where slavery was becoming unpopular and not needed and was seen as a set back. Abraham also decided to free slaves after the war or until he had a definite victory over the South so when Abraham did free them the South couldn't recover.

ghana achieved independence peacefully, while algeria gained independence through an armed struggle.