The lecturers in that video do make good points as the the very philosophical nature of slavery in the Americas. They lean very heavily on the economic argument, which some historians have used from time to time to argue something very similar. The central idea is "Slavery was ended not for altruistic reasons, but economic." And there is some validity in it. The South had traditionally dominated American politics and the American economy. But the rise of the Northern industrial sector challenged the South's economic position. Slavery enabled the South to maintain its economic position, and was ins some ways the avenue by which the North and South could bicker over who was the economic hegemon in America.

However the lecturers in the video take this argument way too far. The fact of the matter was, no matter how racist they were, and how uncaring they would become after the war, Northern abolitionists really did believe in the freedom of blacks. The movement to free the slaves in the United States reflected a moral shift on the attitudes of many Americans towards slavery. They began to accept that Africans were human beings, and that they were entitled to the same basic rights as whites. This shift came later in the United States, but it represented a global shift in attitudes towards slavery which saw the institution end in France and Britain.

So, they are correct in arguing that there were economic aspects to the end of slavery. But they are wrong in suggesting that there were no altruistic aspects as well.

I would also caution you about things put out by groups identifying themselves as "Black Hebrew Israelites". There are factions of that group which are decidedly black supremacist, and are as bad as some white supremacist groups in their use of rhetoric, propaganda, and historic revisionism. Im not suggesting that the lecturers were black supremacists, but the poster of the video and the commenters below seem awfully suspicious.