If you could give a slightly fuller summary of the video's argument and conclusions that would be cool - watching 40 minutes of YouTube is a bit of an ask. The video is produced by this fellow, Stefan Molyneux, who seems to be a strongly libertarian figure. Obviously, no political tendency has a monopoly on intellectual honesty or truth, but it is helpful to know what angle a figure might be looking from, and how their biases might affect that.

In relation to slavery generally, then it's correct. Involuntary servitude has been a virtual constant of human civilization. But it's justification and exact form has not: "Race" as understood as the later Euro-American slavers and us today was a concept that did not exist for much of history. The Romans, the Arabs, the Barbary pirates, and many of the other slaving societies justified slavery in other ways: religion, a perceived civilizing mission, war booty, criminal justice, etc.

If he's talking about the Trans-Atlantic slave trade specifically, then it seems impossible to deny the centrality of racism as a justification, at least for most of the period the triangular trade was in motion. Of course, it wasn't the only aspect - IIRC, racism as we understand it developed after the trade began, essentially as a way for slaveowners to sleep at night. Other users on here - u/khosikulu, u/FatherAzerun, u/Carol_White, u/sowser, and u/textandtrowel, to name a few are far more knowledgeable than me, though, so maybe one of them will give you a better answer and correct anything I've got wrong.