A big problem IME is people tend to define "simple" as "written in a style I prefer". For example you can extract a series of 10 obviously-related methods from some 2000-line God class into their own class, but have others who are used to a more procedural coding style complain that the indirection is "hard to read" because they need to open a new file. This despite the facts that others find the God class "harder to read" because it contains 2000 lines of code doing everything under the sun, and that class is objectively harder to maintain/change for everyone because nobody knows what things are necessary to change to achieve some goal, because there are no logical boundaries between code functions so you can't tell what needs changing without reading everything.

Cue endless bikeshedding in the name of "simplicity", which nobody is using an objective metric to define.