Carlo Cipolla's basic laws of human stupidity

I only knew the late Carlo C through his valuable Guns, Sails, and Empires: Technological Innovation and the Early Phases of European Expansion, 1400-1700 (1965), but on Googling him just now I came across this 1988 essay "The Basic Laws of Human Stupidity". They are:

1. Always and inevitably each of us underestimates the number of stupid individuals in circulation.
2. The probability that a given person is stupid is independent of any other characteristic possessed by that person.
3. A person is stupid if they cause damage to another person or group of people without experiencing personal gain, or even worse causing damage to themselves in the process.
4. Non-stupid people always underestimate the harmful potential of stupid people; they constantly forget that at any time anywhere, and in any circumstance, dealing with or associating themselves with stupid individuals invariably constitutes a costly error.
5. A stupid person is the most dangerous type of person there is.

I think that may be the most moving analysis of the human condition I have ever read.