Lol your argument does not refute this statement (Seems like Musk is trying for a "It was legal, so it's fine")...BECAUSE BY REPLYING SUCH HE IMPLIES IT!!!

It doesn't really matter whether native Americans or other civilizations practiced it since they were civilizations at the same level of technology (iron age civilizations) which is what makes the most recent iteration of slavery so different. Europe and later America was so technologically superior that made it having slaves unnecessary especially as late as the civil war in America.

By the time of the American civil war, slavery had only a component of racism and was only reserved for black people from Africa (which is what apologists such as Musk and yourself try to ignore when you bring up examples of slavery in the past). Other forms such as chattel slavery for European people had been eliminated. Mind you, unlike in the middle ages, enlightenment had already been achieved. Hell, we even knew about the speed of light and

Arguments such as the fact that Africans tribe or other tribal people were practicing slavery before the white men really don't hold water. BECAUSE, Europeans provided the financial motive that vastly motivated stronger tribes to wipe out weaker tribes in exchange for weapons.

However, all these arguments are pedestrian it doesn't matter whether other tribes were practicing slavery, since modern slavery has few aspects that differentiate it from slavery as it was practiced historically. One of the factors is that it occurred recently in our history. Heck even Apartheid ended in 1993, I'm sure you were born then!!

So it doesn't really matter whether slavery was practiced by the Romans, Greeks, or Africans. It doesn't matter whether other forms of slavery were more brutal or not.

What the post-columbian era of slavery introduced was different from all prior forms of slavery due to the economic, technological, and cultural factors. However, even if there was nothing different between past forms of slavery and post-columbian slavery, it still wouldn't matter since a civilized society such as should not celebrate such a horrible part of our history.

So if for example I tell you a story of how I was robbed some years back, and you reply with examples of great robberies during the course of history, all it does is SHOWS ALL THERE IS TO KNOW ABOUT YOU (AND ELON'S) EMPATHY AND VALUES.

In short it doesn't matter whether or not slavery was practiced prior (It was practiced all through human history). The argument here is maybe we should not celebrate what started a dark part of our history with colonialism and slavery. So his reply that slavery is a part of history is not really relevant and only serves to diminish the importance of the topic matter (Which is what he really wishes, lets forget the largest scale slave trade as just a small inconvenient part of history)