It is not just about stupidity. Every day, some of the smartest people in the world get out of bed and go on to make some of the dumbest choices. A decorated academics professor may have an unreflected world view and a doctor may smoke their health away. Humans are majorly influenced by their upbringing and experiences, and when there is enough damage caused, a population will suffer the consequences through the failure of the individual.
This is why I never cheer when a tragedy happens in the world, even when it hits the worst people imaginable. It would be like throwing a snowball towards somebody standing uphill on a snowy mountain slope: When they fall over, the avalanche will not care who caused it.