Well actually many historians may point out that many of the European philosophers stole ideas from the Africans, so in a sense African philosophers have contributed to modern society, but they will never get the credit because as colonization came along, their culture was robbed and destroyed. Same thing can be said for other groups. It can also be said that many women pioneers will never get their credit either.
I can't disagree with anything that has been posted, but I have to concur with post #5 for the practical reason that there is a limit to how many topics you can cover in a typical person's education. It makes sense that you are going to focus on histories and philosophies that have most directly affected your own society.
However, that doesn't mean we shouldn't make some effort to introduce material that would lead to a greater understanding of different cultures. We just wouldn't be able to go into much depth.
As someone who is professionally interested in the history of Southeastern Indians, I certainly see where you're coming from.
As for your broader philosophical point about history, no serious historian claims anymore that there is a real story. The problem is that many history curricula are still so focused on content over the epistemological aspects of history as a discipline that it is difficult to make students understand what history is. The problem is only exacerbated when dealing with peoples who left fewer written records. A highly skilled researcher using ethnohistorical methodologies can learn much about, say, Tuscarora Indians or Igbo in Africa by reading what a 17th century trader had to say about them, because they can cross-reference these sources with oral tradition, archaeological records, and so on. A high school student reading the same document will probably just take it at face value.
I do not really think that it is such a huge problem that we do not learn about African philosophers. The main reason for this is that, regardless of how brilliant they were, they did not have the same impact on our modern world that European philosophers did. We can't study everything, so we have to prioritize those subjects that have a greater influence on our society. Some things, like African philosophy, get lost because they simply haven't been as central to the creation of our society.
You are correct that history for many years was Euro-centric; in fact many colleges teach History 101 as "Western Civilization." The reason for this is for so many years, western civilization was considered "the" civilization. The perception that European culture was superior to all others was predominant. This has begun to change over the past decade or so; in fact ETS now offers a course in World History which is no more than 25 % European history. Even so, change occurs only slowly. In time, I think the study of history will become less Euro-centric, but this will occur only with the passage of time.
You are also correct about the influence of point of view on historical interpretation. I teach my students to consider point of view in evaluating historical documents in an attempt to determine the accuracy of historical narratives. However, for those who consider history to still be memorization of facts, the potential for error and misinterpretation will remain.
It is a shame how ethnocentric education is, but it reflects the ethnocentric nature of mankind. It is not simply African philosophy and culture that is neglected, but also many others, including Asian and Indian. This contributes to our abysmal ignorance in international diplomacy and business, and the key to solving this problem clearly does lie in education, the earlier the better.
However, there are many forces that work against this. For example, textbook publishers create social studies textbooks based upon the needs and politics of the largest states, usually Texas and California, because this maximizes their sales. Those textbooks are often then distributed nationally, which means that the greatly ethnocentric and even racist politics of Texas are presented as "history" across the country. Another force that makes it difficult to solve the problem is that of the local nature of education. The state may set curriculum, but each local school board pours content into that curriculum, thus assuring that its own prejudices are perpetuated.
It is up to teachers, and maybe even up to students, to see to it that other cultures are attended to, not simply in social studies, but across the curriculum. How many students even know that some of our greatest concepts in math are from an Arabic culture? Should we not be reading literature from other cultures in our English classes? Are not the ideas of Hinduism and Buddhism of value to us? As busy as we are and as much ground as we have to cover, there is no excuse for our neglect of the rest of the world.