Documentation that has been obsessively dumbed down i.e., simplified to the point where only a cretin someone who can't do anything right could bear to read it, is said to have succumbed to the "drool-proof paper syndrome" or to have been "written on drool-proof paper." For example, this is an actual quote from Apple's LaserWriter manual: "Do not expose your LaserWriter to open fire or flame."

It was in this world that "user friendly" was first translated to "dumbed down," where "drool-proof paper" was coined to describe documentation (computer hardware and software instructions) that had been dumbed down to the point where only a cretin could bear to read it.