“No matter what, the operating moral premise of information design should be that our readers are alert and caring; they may be busy, eager to get on with it, but they are not stupid. Clarity and simplicity are completely opposite simple-mindedness. Disrespect for the audience will leak through, damaging communication.”
So, in my interpretation, the best way to avoid stupidity is for oneself to not be stupid in the first place. That is, stupid is as stupid does. Or, in other words, acting stupidly invites further stupidity.