Why does the West place a lower value on African lives than it does on white Western lives?

www.bbc.com/news/world-africa-30777066

How many Nigerians have to be killed before the West starts to care? How much depravity has got to be visited upon these desperate people before the West takes note?
What happened in Paris last week is an outrage and, rightly, the world has reacted but why does the West not react when Boko Haram terrorises Nigerians? Why are black Africans not 'worth' as much as white Westerners? Why do the massacres of black Africans not stir the emotions of the West? Surely, the difference in the reaction of world leaders to the two situations, the outrageous attacks in Paris and what is happening in Nigeria, it defines the West as racist.
Nigeria is burning, it's a hell hole, Boko Haram is instituting a genocide, children are crying out for help, parents are witnessing the massacres of their children, the silence of the West must be deafening. Jews, gypsies, gays and others were in concentration camps during the Holocaust, waiting, hoping, every minute that the Allies would come to their rescue but it was years before it did arrive. Nigerians today must be hoping and praying just like Nazi victims were hoping and praying decades ago.
What a tragic indictment of Western humanity and society!