Well as an ex-Ruse, I can say lots of students are actually naturally smart.
And we do have sport, contrary to popular belief... Our sporting teams are about average in the area; not the worst, not the best.
Whether the atmosphere is competitive is dependent on the grade culture. In my grade it wasn't very competitive, but common jokes targeted towards the smart people were, "hope you get 100 ATAR, so I get better scaling!" So at times there was complacency.
There is quite a lot of inter-grade interaction, so people typically know each other from different grades because of all the school activities we have: Musical, Cadets, etc. However, the higher grades always give the lower grades crap about how dumb they are. Ruse will probably fall out of its place within the next 10 years? (...famous last words)
Personally, I'm not very smart. I'm one of those people who are categorised as "study to get good results". I don't mind being labelled as that because I believe in working hard to get the results; putting in the hard yards is satisfying as you feel you deserved all your marks.
Nevertheless, there will always be overarching comments about schools and unavoidable in BoredofStudies (troll central).