Why is Greece a "he-goat"?

In Daniel 8, Daniel sees Persia falling at the hands of the Greek Empire. Persia is symbolized by a ram (the two horns representing Persia and Medea) and Greece by a "tzfir-izzim", which apparently means a "he-goat" (se'ir). Turns out, certainly the last part about the tzfir, is a fascinating bit of symbolism. In Efraim Tzoref's book "Yosef, Viceroy to the King of Egypt", Vol. 1, pg. 177, while discussing symbolism in dreams, he writes (translation from Hebrew): "Plutarch (Hadrian's teacher from the 2nd century CE) recounted: When Alexander the Great (from the 4th century BCE) laid siege upon the walls of Tyre and was not able to conquer them for a long time, he lost hope and decided to withdraw. That night he saw in his dream a satyr dancing before him victoriously. In the morning, Aristander, his dream-interpreter, interpreted the dream for him, that he would indeed manage to defeat Tyre, as the word satyr is comprised of Sa - yours and ...