They simply assume that Italians and various others have “swarthiness” from the same source (falsely, according to the best info I can find without really caring).
Mediterranean Europeans are typically noticeably darker than Northern ad Eastern Europeans. Eye and hair color also clearly have a North-South and West-East gradient.
Mediterranean Europeans are typically noticeably darker than Northern ad Eastern Europeans. Eye and hair color also clearly have a North-South and West-East gradient.