It has nothing to do with IQ, and everything with turning people into cogs in a machine. Following the rules, no matter how inane, is safe. Making a judgment call to break the rules exposes one to risk, and people who will review it later will likely be in the same conundrum themselves (i.e. it's always safer for them to conclude that breaking the rules was not justified), all the way to the top.

This is also why the larger and the more hierarchical any organization is, the more sociopathic it is as a whole, even if its bureaucracy is ran by people who aren't.