I don't know my African history well enough to dispute anything you have said. As an outsider, it has always amazed me how people think that because a person is part of a group - skin color, religion, etc., they will vote or act the way the group generally does.
If you and I lived next to each other, our relationship would be easy to describe. This is not true of the relationships between countries. International relationships involve many factors, some of which the public may not know.
I was an Obama voter two times, and I admit he did not accomplish everything I hoped for. Being a person of color and president of a racist country must have been difficult, and I would like to believe that he did the best he could with the information he had at the time.
To the best of my knowledge, the situation in Lebanon was not created or made worse by western intervention. It appears that the various factions are not willing to work together for the common good. This lack of desire to compromise makes all the relations between countries almost impossible to resolve.
These problems don't absolve America from the guilt of supporting various dictators, but it does partially explain why so many efforts have failed. The old saying, "When two men fight, the third man wins" might explain why outside forces conspire to further conflict in many areas.