The threats cited by U.S. officials to justify AFRICOM aren't imaginary. Global terrorist networks do seek allies and recruits throughout the African continent, with potential impact in the Middle East, Europe, and even North America as well as in Africa. In the Niger Delta, the production of oil has been repeatedly interrupted by attacks by militants of the Movement for the Emancipation of the Niger Delta (MEND). More broadly, insecurity creates a environment vulnerable to piracy and to the drug trade, as well as to motivating potential recruits to extremist political violence.
It doesn't follow, however, that such threats can be effectively countered by increased U.S. military engagement, even if the direct involvement of U.S. troops is minimized.