Could it be that Greek philosophers were so mistreated because they imported a foreign and therefore subversive worldview? For example, Pythagoras, the "father of geometry" and the first Greek philosopher, was purported to have traveled to Egypt. He settled in Italy and practiced a simple, communal life, the goal of which was to live in harmony with the divine. To that end, he prescribed a regimen of purification that included dietary restrictions and periods of silence and contemplation. He taught the kinship of all life and the immortality and transmigration of the soul.
Stolen Legacy argues that Greek philosophers were not the originators of Greek philosophy, but that they derived it from Egyptian priests. James posits that Greece during this period of "enlightenment" was, in fact, constantly engaged in war and internal conflict, creating an environment not conducive to the evolution of philosophy. He bluntly states that Greek philosophy was the off-spring of the Egyptian Mystery System and that the Egyptians educated the Greeks.
Upon its publication in 1954, Stolen Legacy was not well received; however, it has remained in print to this day as a controversial chronicle of the possible African origins of classical civilization. Even if you don't agree with all of James's conclusions, the questions he asks and the theories he asserts are fascinating to anyone interested in studying classical civilizations from an African-centered perspective.