Using the same logic, Western countries tried to colonize Russia in 1919 and Nazi Germany colonized quite a bit of Europe during WWII.
An assertion about "Africa" is like an assertion about "Asia", which includes everything from Russia to Thailand to India to China to Turkmenistan to Iran to Japan to North Korea. There are few assertions one can make about all of Africa, which covers Egypt to Morocco to South Africa to Kenya to Liberia to Madagascar, and so much in between.
> the only continent that produces what it doesn't need but imports all that it needs
That's normal trade behavior. You produce things in which you have comparative advantage, then trade them for things that others produce more efficiently.
France produces far more wine than it needs and Japan produces far more cars than it needs because both are great at making those things. Then they trade; resources are used most efficiently, because both are more efficient at producing their specialty; and consumers get the best products in the world. You get more for less. Otherwise you'd have lots of Japanese wine and French cars.