Interesting statement, but historically false.
I don’t defend slavery, which I condemn. But i would look at history before i judge.
If you look into history, slavery means different status for different people.
For instance, at the height of the roman empire, it was fashionable to free ones domestic slaves who were minor family members. Freed slaves became citizens, and some won power, fortune and fame.
And the status of slaves was constantly improved.
More fundamentally, in very ancient history, the winner tended to kill the vanquished. When it became profitable to keep in alive, after the beginnings of agriculture, slavery was a progress.
We see slavery from the point of view of Muslims and European slavers and from this point of view, it is morally wrong. The aim of was to find cheap labor, exploited in dreadful conditions. It was justified by a racist ideology.
I can understand that our ancestors were born in a world in which slavery and racism were looked on as natural truth. I can take the good sides and achievements of a slave owner, when judging him. Many of the founding fathers of USA were slave owners.
A last point. Many Europeans came to America as indentured servants, which is globally temporary slavery, willingly or not. The distinction between Indentured Europeans and African slaves was not clear during the beginnings.