Overall what you say is true, however there has been a problem with islam vs. non-muslims in Africa for decades which has become much much worse in the last few years (as the percentage of muslims in many countries there has skyrocketed). What is happening in Kenya right now is not primarily tribal as the drive by media would have you believe. It has a veneer of tribalism but is primarily driven by muslim agitation.
The untold story about Sub-Saharan Africa is that the percentage of muslims compared to the percentage of christians has actually fallen.
There were barely ten million christians in Africa in 1900, but there are projected to be over six hundred million by 2020.
I can assure you that Kenya’s crisis is primarily tribal. (Some of the most bloody crisis in Africa are tribal in nature: Rwanda, Burundi, Congo, Sierra Leone, Liberia).
Let me correct you, the problem with Islam vs Christianity in Africa stems from the fact that the number of Christians in Africa has skyrocketed.