From a quick look at the rest of his Wikipedia page, it looks like he was very happily slave trading (e.g., selling slaves captured in wars of expansion) and only started complaining when the Portuguese started enslaving his subjects in a way that violated the prior Portugal-Kongo arrangements.
He was definitely not arguing from a standpoint of moral aversion to slavery or the slave trade per se. It is simultaneously true that many African nations and cultures were proudly slaving/slave-trading, that this was a moral horror that cannot be excused, and that the effects of slave trading on a mass scale destabilized the course of African statecraft.
From a quick look at the rest of his Wikipedia page, it looks like he was very happily slave trading (e.g., selling slaves captured in wars of expansion) and only started complaining when the Portuguese started enslaving his subjects in a way that violated the prior Portugal-Kongo arrangements.
He was definitely not arguing from a standpoint of moral aversion to slavery or the slave trade per se. It is simultaneously true that many African nations and cultures were proudly slaving/slave-trading, that this was a moral horror that cannot be excused, and that the effects of slave trading on a mass scale destabilized the course of African statecraft.