It is wrong to judge people by their outward appearance because what one sees physically is not what's in the heart. Some people do not dress well but that does not mean they are stupid or have low thinking or reasoning capacity. It just means they like wearing like that. Take for example street children. One might just sneer how dirty, useless they are and that they do not much or won't be of any help. However, these children can outstand someone with their intelligence.
On another note, at times physical appearance does speak a lot about a person. Especially when it comes to dressing. Am not sure in any other countries but ladies who wear with a lot of nakedness in some parts of the bodies makes them look cheap and prostitutes. A man might not want to take such a girl to introduce to his parents.
My conclusion: Do not judge someone by his/her appearance but the appearance on the other hand tells one much about that person. They say actions speak louder than words.
I think the above is not a conclusive statement. Makes me wonder. And think a lot.