I have actually never seen any serious historian or classics scholar argue for white supremacy. The only people who concern themselves with race are some crackpot alt-righters who don't know anything about history and on the other side wokes who interpret everything as being about race.
Not sure why a Syrian is considered a person of color and an Italian wouldn't be. Both countries have a variety of shades, with the majority being olive skinned. Just look at the Hafez al-Assad or his son (what "race" would they be?) Same with North Africans. Look at the series "The Looming Tower" and compare actors Louis Cancelmi (who is of Italian descent) and Tahar Rahim (who is of Algerian descent). Both of them have the same shade of color.
This brings us to the question of "race" of Septimius Severus. Once again, the fact that this is even debated speaks more about current woke sensibilities than anything else. He was born in Africa, and was probably of mixed Punic and Roman descent. Punics were of Phoenicians stock, meaning originally from the area of current Lebanon and Syria. His mother was from an old Roman aristocratic family. Severus did not look any different from the average Roman, meaning he probably had olive skin.
He certainly wasn't "black". In fact, the Historia Augusta's biography of Severus has an interesting story:
"On another occasion, when he was returning to his nearest quarters from an inspection of the wall at Luguvallum in Britain, at a time when he had not only proved victorious but had concluded a perpetual peace, just as he was wondering what omen would present itself, an Ethiopian soldier, who was famous among buffoons and always a notable jester, met him with a garland of cypress-boughs. And when Severus in a rage ordered that the man be removed from his sight, troubled as he was by the man's ominous color and the ominous nature of the garland, the Ethiopian by way of jest cried, it is said, "You have been all things, you have conquered all things, now, O conqueror, be a god.""
Before he died, Severus was in northern Britain inspecting the troops. While there, he saw an "Ethiopian" soldier. For ancient Romans, Ethiopian was usually synonymous with black. So he saw a black soldier, which he took as an omen of his impending death. Black was the color of death in ancient Rome. Once again nothing to do with race, just the color. However, had Severus been "black" himself, then the sight of a black soldier would not have bothered him.
Anyways, why is Severus darker in the picture than the rest of his family? Well, people tan, meaning they change color. As a soldier he would have spent a lot of time in the field in the sun. In ancient Egypt, if you look at family statues, the men were usually depicted as darker, and the women as extremely pale. This is because women of the nobility spent most of their time indoors.
In places like medieval Europe or Asia, white skin was not a racial thing, but a class one. If you were pale, that meant you were from a higher social class. The lower classes had to labor outside, so their skin was not "white". That is also why you can often see women from Asia have umbrellas on sunny days. Once again, it's not a race thing, but a class one.
Which brings me now to Winckelmann's quote. To interpret that quote in a racial way is once again a sign of current woke debates, and doesn't really reflect what he actually meant. Winckelmann (who was openly gay by the way) meant it more in a philosophical way of ideal Platonic forms and referred to the material the sculptures were made of, which was white marble. He referred to the marble and not race. Anyways here is a good scientific summary of his thoughts:
https://www.tandfonline.com/doi/full/10.1080/00233609.2020.1788636
I find the entire debate about race in classics as totally out of touch with reality. Classics aren't racist. No serious classics scholar or historian in today's world argues for white supremacy. It's more of a strawman argument from the woke side. The Romans weren't white, nor black. They were Roman.
