The Babbage Society at Work?
Diesel, a clothing brand I had never heard of, has an ad campaign with the slogan Be Stupid (seen via James Lileks). I suspect it was originally supposed to be aimed at people patting themselves on the back for being so intelligent, until the ad people realized that self-congratulation was now in disrepute, so they went with the opposite.
On the other hand, maybe it was the Babbage Society. According to Country of the Blind by Michael Flynn, the Babbage Society was trying to foment stupidity by turning “wise guy” or “smarty” into insults.