When Frank Herbert wrote Dune, computers weren't built into nearly every electronic consumer product that you bought like they are now. They were hulking colossi that occupied whole floors of buildings, and required teams of people to operate them. Control systems in aircraft and production plants were generally quite simple, and usually implemented as analogue rather than digital, devices. I expect he envisaged that the latter sorts of mechanisms would be acceptable whereas machines that were designed to replicate the cognitive functions of man would not. There is the occasional muttering in the books when some Ixian device pushes the boundary.