They have wars because their borders were drawn by colonial exploiters with no regard for the ethnic groups of the people living in the land. Africa should have twice or three times as many countries than it has now.

There weren't many nation-states before that - the keyword here is "nation" which is quite different in meaning from the word "tribe". When you have a ethnic map looking like kaleidoscope nation states aren't very sensible. The few stable African countries - RSA, Senegal, Ghana have more than the average number of ethnic groups even for Africa.

Also, the United States and other wealthy nations destroyed some African democracies in the 60s and set up puppet dictators.

I'm sorry but while true, this is not the whole truth. The US wanted to stop Communism in Africa and it did back some "right-wing" butchers and dictators against the left-wing ones. The record shows that communist dictators are almost always much, much worse and even when they are in power they mismanage the countries into oblivion. Yes, I agree that there had to be a better way, but you cannot simply claim that it was done from greed and wickedness. That just makes you sound the <em>Pravda</em> newspaper:
http://www.gazeta-pravda.ru/pravda/logotip.GIF

The USSR, its Warsaw Pact allies and other communist countries like China and Yugoslavia, are much more responsible for Africa's troubles than the US. Communist provided "freedom fighters" with arms and corrupted and manipulated governments. Money from arm sales were crucial for some of these countries, because they badly needed foreign currency. Also "world revolution" was a stated goal and you had to have a global war (read some Marx, Trotsky and Lenin if you don't believe me). Che Guevara and Mao thought that conquering poor countries was a good way to win globally and their post-Stalinist communist plot was really the only paradigm commies could realistically follow after the invention of nuclear weapons (you obviously cannot launch a WWIII to conquer Europe and the US).

The Communists actually won in most of Africa around 1991, with the most notable exception of Zaire, which was ruled by US-backed kleptocrat who then became "non-aligned". They obviously wiped out the anti-communist forces, but it wasn't all pretty. The new rulers didn't know how to rule the countries and even the peace was short-lived because the poverty which they only made worse made it easier to create yet another generation of warlords.

Africa had the bad luck of becoming the battleground of the Cold war.

The USSR did in fact win the Cold war in Africa - most of the regimes were pro-Soviet, but that brought little value to the Communist block. Che Guevara was wrong - the communist system of world revolution wasn't sustainable and no external success could remedy the many flaws and internal problems the USSR had.

For a horrific example, learn about the U.S. backing of Congo's dictator and the resulting wars in which 5.4 million people were murdered and millions of women raped. God Bless America.

Are you sure the U.S. had chosen a side in the Second Congo War? After the Cold war, Africa stopped being so important. Most of the leaders on both were pro-Soviet during the Cold war. I don't see how

America is currently loved in most of Sub-Saharan Africa. Clinton and Bush had a friendly relationship to Africa (the latter greatly increased the volume of the aid, making the continent one of the few places in which he was popular) and Americans just elected a president who has huge ties to Africa.