Why did imperialists seek possession of colonies that had extractive economies?

The reason why imperialist seek possession of colonies that had extractive economies is that they wanted to gain the advantage of the global resources in the market especially in the product like flours and wheat. They wanted the resources so that they can expand their trade and widened their market locally and internationally.

More than 4 million enslaved hunan beings in the south and they touched every aspect of the regions social, political and economic life.