For some reason I had assumed that the Cadians were the lowest common denominator. I mean it isn't like they were Catachans, those guys grew up on a jungle death world! The trap a fell into is that although Cadia isn't technically a death world, the Cadians treat it as if it is.
It says in the fluff that Cadians learn to strip a lasgun before they learn to walk. They are inducted into the guard at age 14. The thing I forget about the Cadians is that they are all badasses! These guys are like the Green Berets, Navy SEALs and the SAS all rolled into one.