Bah, you every actually become friends with such people? It is possible, you just have to do it one-on-one rather than approaching the whole group, then if you do this with the majority of the group you'll find yourself a part of it without having changed a thing about yourself. If you'd take a little time you'd find out they have the same insecurities anyone else has and it just manifests differently. Most people have a group of friends and feel insecure outside of it, likewise within those groups of friends they have the drive to think of things to make them feel their friends are the best. In most cases when a different subculture looks at preps, they tend to say "oh they think they are so cool, what losers". But you'll notice that's a superiority complex as well, attaining the very same character that you criticize them for.
I've found that in certain subcultures, the style of clothing while distinct isn't limited to a specific brand, mostly due to the nature of the style and in some cases lower income. So those groups tend to find their uniting elements in things like what genres in media they are into and what kind of things they are definitely not into. Not only this but they tend to hypocritically frown upon clothes that other groups identitfy themselves by (if clothes mean nothing why is it not cool to have an abercrombie shirt in your wardrobe?). Then in some cases a person just doesn't really have any friends so it's very easy for them to get a superiority complex, especially if they find the majority of their social exchange on an internet forum where such things aren't even identified (I'm not saying this is true of you, just that it happens).
But what I'm getting at is you should take some time to put yourself in their shoes for a little bit. It seems (at least in my area) that a lot of them tend to be in sports, so a group mentality would probably be stronger on them. Then in many cases they tend to have very busy lives, their time is spent with others, so their thoughts are shared with others. There aren't too many criplling aspects of life to make them ponder the universe, and even when there are they are too busy to really explore them. Usually a friend like you can help them do that and see more in life, although it does take time. As for the stealing, if one of them did do it then that does show poor character. However while I wouldn't recommend letting them go scott free, it is another action that has a reason, and dealing with the reason to make them a better person is better than a slap on the wrist.
Sorry for ranting, I just have many friends in all sorts of social circles and I've found that everyone is the same. In judging others as a group you place yourself in a higher group, such is very haughty and only perpetuates the issue on both sides. Group mentalities can be dangerous, but so can overly individualistic mentalities. The fact is everyone is interdependant upon a certain group of others in some way shape or form, so in turn they will find different ways to make that easier. Also judgment is the lowest form of understanding, it can only punish bad values and has no redemptive power to bring about good values. For that you need forgiveness and love, sorry if that sounds a little hippie but it's true.
If you think your understanding is better, then it's selfish to keep it to yourself. To understand them you need to look past faults and rightly invest into them, and they'll also understand you. If thats not something you're willing to do, then it's pretty hypocritical to be judging complaining about them. It's real easy to look at what they do and say they are bad people, but although much harder it's much beter to get to know them and find out why they do what they do. It is difficult at first, but through it you start to understand the human condition a lot more, and it makes it easy to look past things you don't like at first and more easily to relate to people. Then after awhile you'll find you never get caught up in bad social situations that we always see on shows like The Real World.
