The Afro-Phoenicians are mentioned several times in this chapter. Why are they mentioned?

In my opinion, they are mentioned to highlight the frequency in which they are not mentioned.... and the fact that although their case hasn't been proven... it is worth a discussion.

American history textbooks promote the belief that most important developments in world history are traceable to Europe. To grant too much human potential to pre-Columbian Africans might jar European American sensibilities. As Samuel Marble put it, “The possibility of African discovery of America has never been a tempting one for American historians.”22 Teachers and curricula that present African history and African Americans in a positive light are often condemned for being Afrocentric. White historians insist that the case for the Afro-Phoenicians has not been proven; we must not distort history to improve black children’s self-image, they say. They are right that the case hasn’t been proven, but textbooks should include the Afro-Phoenicians as a possibility, a controversy.