I know “why” (the cost of the freed slaves) but I can’t imagine the slaves who liberated themselves with sweat, blood, and tears would be too big on that. Why did they agree to pay? Or, more likely, who forced them to pay?
While you wait, take a look at this answer from /u/LordEiru
https://www.reddit.com/r/AskHistorians/comments/og7krv/why_haiti_is_so_poor/