I don't think much effort was made to get anyone "on board with AFRICOM" per se simply because AFRICOM does not represent any significant policy shift or effort: it's little more than an administrative shuffling of existing programs involving a quite minimal commitment of resources. Much of the reaction has been not to what AFRICOM actually is, which is not much, but to what AFRICOM has been portrayed as being.
Once again, someone doesn't get strategic communication - at the highest levels in the US Government. It's not limited only to the bungling of the Africom announcement.

You guys feel that once you've processed a concept within your system and you are okay with it, then all will be well. Because the innate goodness of America is apparent to all and that the whole World sees the Shining City on a Hill and America is an exceptional nation and Americans are exceptional people.

That mindset is great if you want to communicate with the American public, but the American public is not the only audience worth considering.

My major worry is not what Africom is or is not, but that the creators of Africom either don't get Africa or don't take Africa seriously enough. Neither is good. After Iraq and Afghanistan, you cannot afford to make that kind of blunder.

Africa is huge. The map below shows how massive it is.