The Jargon File (version 4.4.7, 29 Dec 2003):
dumbed down
adj.
Simplified, with a strong connotation of oversimplified. Often, a
marketroid will insist that the interfaces and documentation of software
be dumbed down after the designer has burned untold gallons of midnight oil
making it smart. This creates friction. See user-friendly.
The Free On-line Dictionary of Computing (30 December 2018):
dumbed down
Simplified, with a strong connotation of
*over*simplified. Often, a marketroid will insist that the
interfaces and documentation of software be dumbed down after
the designer has burned untold gallons of midnight oil making
it smart. This creates friction.
See user-friendly.
(1995-04-14)