1) The halachah is that a ben torah must dress (and act) in a way that denotes respectability. The gemara says that one who dresses sloppily and causes the torah to be looked down upon is chayav meesah (Shabbos 114b) (if I gave the wrong place I am sure someone will correct it).
2) Charles Thywitt (considered a choshuv company)shirts were recently on sale for $30. Jos.A.Bank was $26. Hat Box Wrinkle-free shirts were 3 for $100. Mabye I can’t afford to buy non-designer.
3)Somebody who only buys black pants because he wants to portray a certain image is just as into his clothes as one who buys white pants. My point is; don’t pick on the clothing, pick on the image the wearer is trying to portray(the seebah, not the siman, in yeshivishe shprach).