Charles' shrewd observation implies, inter alia, that many "oppressed" are better observers of social life than many those who do it professionally.
The way clothing, and any external appearances for that matter, work can be described as making decisions under imperfect information. If people do not know anything about you, they will judge you but whatever little they do know i.e. your appearance. While it is not the only way they make their judgment, this might be only judgment they pass on someone whom they meet casually or for the first time, because if they dismiss someone based on the appearances, that someone will have no other chance to prove his/her worthiness.
In that way, people who dress up are like good writers - they understand that the first impression they make or the first paragraph of the book they write decides whether there will end up as a success or a flop. Most people have neither time nor desire to thoroughly investigate the virtues of any person or a text appearing before their eyes - they make their decisions based on quick glimpses and if the verdict is negative, they do not give that person or that text a second chance. So while the good first impression does not guarantee future success, the lack of it is almost certain to guarantee future failure.
Those who do not follow that rule either (i) have poor social/writing skills or (ii) are so self-centered that take it for granted that their own virtues will shine under any condition, no matter what they do or (iii) do not give a shit what other thinks of them or their writing.
Much has been written about that type of behavior in various types of social studies - status generalization, behavior in public places, rationality and information asymmetry come to mind. I am surprised that many social science professionals on this list ignore this research and resort to puritanical banalities about deceptiveness of external appearances.
Wojtek