According to Osho, about ninety percent of 'idiots' are manufactured by society and only ten percent are born - and even those exist because a competitive, hierarchical culture needs them. Constant comparison, prohibitions ("Don't!"), imposed ideals and media manipulation cripple natural intelligence. If people were allowed to blossom in their own nature without coercion, such stupidity - and the elevation of photogenic leaders - would largely disappear.
Most idiots are made when society keeps scolding, comparing, and shaping people instead of letting them grow naturally.