When Obama wrote that many people "had been enslaved only because of the color of their skin," he was repeating a common piece of gross misinformation. For thousands of years, people enslaved other people of the same race as themselves, whether in Europe, Asia, Africa or the Western Hemisphere.
Europeans enslaved other Europeans for centuries before the first African was brought in bondage to the Western Hemisphere. The very word "slave" is derived from the name of a European people once widely held in bondage, the Slavs.
As for economics, Obama thought that Indonesians would be worse off after Europeans came in, used up their natural resources and then left them too poor to continue the modern way of life to which they had become accustomed, or to resume their previous way of life, after their previous skills had atrophied.
This fear of European "exploitation" prevailed widely in the Third World in the middle of the 20th century. But, by the late 20th century, the falseness of that view had been demonstrated so plainly and so often, in countries around the world, that even socialist and communist governments began opening their economies to foreign investments. This often led to rising economic growth rates that lifted millions of people out of poverty.
Barack Obama is one of those people who are often wrong but never in doubt. When he burst upon the national political scene as a presidential candidate in 2008, even some conservatives were impressed by his confidence.
But confident ignorance is one of the most dangerous qualities in a leader of a nation. If he has the rhetorical skills to inspire the same confidence in himself by others, then you have the ingredients for national disaster.