The West African countries are facing deadly violence from jihadist groups, but their armies are also accused of crimes against civilians. The ICC's mission is to prosecute the perpetrators of the most serious crimes, such as war crimes, when countries lack the will or capacity to do so themselves.
This is the crucial undermining aspect of the ICC; that the high-minded ideals of justice are only realistically upheld for economically depressed, non-Western states. Why should they stick around, when their votes to hold criminals accountable in America, Israel, China, etc are useless? The racism and classism inherent in these attempted international institutions, starting with the UN, will lead to their unraveling if not addressed.