Computers, robots, artificial intelligence …modern technology is good for a scare, because the idea that a machine can become sentient and not have our best interests at heart is terrifying. Hollywood takes advantage of that fear in movies good and bad. Remember how you felt when HAL 9000 said, "I can't do that, Dave." in 2001: A Space Odyssey? The Terminator, War Games, and plenty of other films will horrify you in the same manner. Relive that fear in a list at Gizmodo. Link
Notably Colossus, who's mission is to protect man from himself (BTW if you like this story, read the original Colossus and the sequels, Fall of Colossus and Colossus and the Crab by D.F. Jones).
The MCP was also more for running things to help, "I can run things more efficiently than any man...", even if it meant hacking into other systems to do it. I general TRON was more about recovering stolen data.
Of course HAL had bad management instructions that messed with his logic.
Not saying I want to be ruled by computers but I think there's more to the computers' side on some of these...