That is not the same thing as "Just stop communicating" or "shut up". I shouldn't have been so terse. Without the verbal cues you made a different assumption about what I was trying to say.
I never used the term idiots, that's you putting someone else's words in my mouth.
It's hard for me to imagine how a person can make a mistake in a given domain without being at least bit incompetent in it, hence my point about competence/incompetence existing on a continuum.
Edit: ...and if the person were malicious, it wouldn't be a mistake to begin with.
Mistakes aren't always made due to incompetency and extremely competent people still can make mistakes.
I think most of the "seven factors that lead to stupidity" could still affect someone very competent:
We'll just have to agree to disagree regarding human nature.