I can't agree with the assumption that people, in general, are ignorant, and accept all information spoonfed and at face value. I've come across this opinion a lot (it seems especially prolific on the internet) and I don't really want to speculate on whether it is cultural, subcultural, age-based or has other origins. It is based on a very limited observation of a very large population.
In a game world like Shadowrun it is certainly easier to perceive the average person as a mindless drone. Bull's right - the game material encourages it! Beyond simplification, I believe the purpose is to help set the PCs apart as 'special'. They are above the general population in something more key than even armament or skill - knowledge.
The desire to have "us" and "them" when it comes to understanding and media savvy is strong. In SR, it is obvious. "Us" are 'runners and "them" are corps, gov'ts, law, dragons... pretty much everyone else. I think things are much more delineated in RL, though.
I think there's plenty of room for wageslaves who exhibit intelligence (if not shadow common sense). That being said, you can't subvert a trope if you don't spend a lot of time building it up first!