Allen Johnson appropriately names this piece "The Forest and the Trees" after his discussion of the invisibility of the social structures which work upon us at all times and how these are incorporated into the basis of culture. He bases his discussions in a sociological point of view and approaches several important factors regarding how our perceptions of race, class, gender, and other inequal institutional ideologies form the premise of social life. He discusses how, when we look universal truths we are actually seeing constructed realities based on cultural beliefs.
The ways in which these social structures come to oppress others has everything to do with how our beliefs, norms, and values become incorporated into our very way of viewing "reality". When one set of values becomes more valued than others, like being heterosexual vs. homosexual, then there is a hierarchical situation in play, one that puts heterosexuality as much more important and valued than homosexuality. This also has real-life consequences because of the norms and standards which have been incorporated into the social culture as a whole.
This leads us to the discussion of how it is useless to blame the victims of the social structures. When we blame the poor for their own poverty, or folk of color for their own negative image, we are essentially forgetting that there is a power structure in control of everyone's lives which everyone in a given society helps to maintain. By blaming the individual for their own failure, we lose sight of the social structures that have not only put a person at a disadvantage, but has also advantaged others unfairly in other regards.
I think that it is extremely important to identify the social structures which constantly try to pass as invisible, especially when we are trying to fix the situations of oppressed peoples. Without understanding how these values, beliefs, and norms come into being, the social world becomes a very ambiguous place which can not be examined fully. This is part of the reason why we take things for granted as human truth in a certain culture.