It is the very definition of being superficial to judge someone solely based on their outer appearance. Let's not fool ourselves that being snobby and judgmental like this isn't superficial and shallow. Let's be more accepting of people and try to work through our issues and stop with all the hate.
I feel that it is human nature to judge someone by the way that they dress. This is not to say that it is wrong. First impressions many times are related to the person's appearance which include the way they dress. In all honesty we probably shouldn't judge a person in this manner.
Dress is used to express ones self and to cover ones self. Some people really care about their clothes; others do not. To judge someone on the way they dress is the epitome of shallow behavior. You are basically taking your own ideas, morals, misconceptions and prejudices and placing them on someone else. Since when are you the moral authority on what is "proper" and what isn't when it comes to clothes? What if you are wrong? Yes, it is very wrong.
Yes, it is superficial to judge someone by the way they dress, but most of us do it anyway. Mocking someone for the way they look teaches our kids that that behavior is acceptable. This can lead to bullying down the line and making fun of other kids, thereby hurting their feelings. Parents should try to teach their kids acceptance of other cultures.
Superficial by definition means on the surface. But the surface often belies a deeper truth. The way in which you dress is a choice, and our choices define you as a person. Much as my diet, decision to exercise, car I drive, job I choose, books i read, music I listen to, etc. All speak to who I am. If the question is, "Is it wrong to judge someone based on the way they dress?" Then I would have mixed answers to that. I have a job that requires me to speak to strangers and there are sometimes very suprising people underneath the surface. But usually, the prejudice is dead-on. If you dress like a thug, it either means you are one or that you want someone to think you are because of the reaction it gets (they leave you alone, respect you, whatever). If you believe Dr. Freud there has to be a reason :)
It is not superficial to judge someone by the way they dress, because the way someone dresses can say a lot about a person. The way someone dresses can show someones social status, as well as their tastes and the subculture they belong too. Some people put a lot of thought into what they wear so it is not superficial to judge them by their clothes.