I had never heard of that term before, but it makes a lot of sense. From my link above:
" Wetiko can be thought of as being a parasite of the mind that operates through the blind spots of the unconscious in such a way that hides itself from being seen as it deceives us into thinking and acting in ways contrary to our best interests."
So, it is kind of the water a fish cannot tell it is swimming in....
And, as Erich Fromm wrote about in "The Sane Society", cultures as a whole can be deemed "sick".
Kurt Vonnegut also wrote in "Breakfast of Champions",
"He attributes the mental illness of Dwayne Hoover and society at large to an abundance of "bad chemicals" in the brain which, when combined with bad ideas, formed "the Yin and Yang of madness." (wikipedia)