I obviously don't know you or anything about your life, but I'm gonna vent at you based on my own experiences. This 1/3 of the class that's all buddy-buddy and goes to the post-exam parties tends to consist of a core group of what I like to call lax bros and cheerleaders, and their assorted hangers-on and wanna-bes. People that forcibly remind me of high school and/or lived for their frats and sororities in college. The rest of us don't really like you and kind of wish you'd just grow up and leave that part of your life behind. We're the same people that would rather drink a beer out of a glass bottle than a keg, because we are adults that have IDs and don't need to drink that ****. We have our own fun with our own friends, and are otherwise perfectly content being casual friends or acquaintances with our classmates.
Just telling the other side of the story.
It's interesting that you seem to look down on this people, yet you're the one being judgmental. Obviously these people have their stuff together, they're all going to become physicians, so why do you care how they choose to spend the little down time that they have? Sounds like jealousy to me.