First, literally has two
meanings, so the use is acceptable because it does not only take on the second meaning.
While I may misinterpret the author of the post you refer to, I think he did not mean to abandon any country but to stop abusing our advantageous position. We shaped most of the current problems by our treatment of the respective regions over the last 200 years. From genocide in Rwanda to the administrative division in the middle East the European powers had their fingers at the root causes. For instance most modern forms of Islam we are currently struggling with (whether the Mullahs in Iran, the Muslim Brotherhood over the Middle east to the most radical IS) originate with Muslim Scholars of the late 19th century that fought against colonial powers.
I have a problem with the additude that the savages can't be help and the following attempt to absolve oneself from any responsibility.
As for your last question: A good first step would be to be less patronising. Western politician mostly act as if all there problems are home-cooked (which many surely are, but not all).
Next up would investment in African infrastructure which would most likely allow more people there to stay in their country - especially the economically driven migrants.
Another issues are current trade agreements with Africa where tariffs hinder them from building up an economy. If the tariffs were removed (like Clinton did already in his Africa policy), they could grow more as well.
Next up is abusing of the fishing policy where European ships empty African waters and crush the local fishing business thereby worsening their economic situation.
These things are just the beginning, I could name many more simple and effective policies, but you should get the gist.
We have the tools in our hand to fight economic migration at its root but we choose to ignore it and utter xenophobic propaganda instead.