What this quote means to me is that we are judged on the way that we appear. People infer certain things about us from the ways in which we choose to present ourselves to the world. We cannot do anything about some aspects of our appearance, but we are in complete control of what we wear. Therefore, what we wear informs the way in which we are perceived and the way that people treat us based on these perceptions.
This seems to me to be both good and bad. On the one hand, it seems very wrong to judge us on outward appearances. We have all heard that you cannot “judge a book by its cover” and it seems that this quote implies that people will judge us by our “covers.” This seems like it would be both inaccurate and unfair. A person might be very intelligent and very diligent but might not care about their appearance. Such a person might be judged harshly even though they would be a good student, friend, and worker.
On the other hand, at least this attitude does not lead to judgments based on things that we cannot change. If we are to be judged by how we look, it is better to be judged on some aspect of our looks that is completely under our control.