In “Colonialism is the Lens and Hip-Hop is the Mirror,” Jared Ball is arguing that the concept of colonialism is one that can be a focus of the perspective through which we view hip-hop music and the culture it promotes. Furthermore, when referring to general hip-hop, Ball is focusing on mainstream hip-hop and the implications it has on our viewpoints. For example, Ball states “Black poverty is not the result of the choice to purchase “spinning rims” as D’mite suggests, it is that fundamental to colonialism is the monopolization of land ownership which forces, promotes and relegates only the purchase of rims and other trifling goods to the poor. And if this basis is understood all systems of media and popular culture can be more clearly identifiable as to their function and necessity in keeping image, thought, and action within what those in control find to be acceptable ranges.” In other words, blaming hip-hop for poverty rates for people of color is not an accurate assumption. What is really happening is that colonialism is still an evident problem that keeps money and property in the hands of a small part of the population while people of color are encouraged by producers of that mainstream media to purchase “trifling goods.” There are stereotypes being perpetuated and reproduced here, and it is designed in a way that keeps systemic oppression happening. Ball is arguing that once we recognize that “those in control” are deciding what is acceptable for different demographics, we can apply the concept of colonialism to this and see who is in a position of privilege and power and who is being dominated and suboordinated.
An example of the kind of message Ball is describing could be found here (not that the song isn't good, because it really is, and it could be perceived as West making a positive statement about mobility for people of color...but that's an oversimplification of implication, which I think is an implicit point in Ball's article).