The earliest Greek sources, including Aristotle, indicate that Aesop was born around 620 BCE in Thrace
True, but being born in Thrace wouldn’t necessarily mean he wasn’t African in ethnicity. There was a lot of movement and migration around the Mediterranean in those days. Also, he was a slave, and slaves were commonly foreigners taken as captives or imported from foreign lands.
Sure, it could just be a spurious tradition that he was African, but sometimes tradition preserves facts that have been lost to history. Personally, I think the nature of his stories, which line up with well known African traditions and not so much with any European tradition, is probably the best evidence.
Did he rape Thrace thrice?