So I think the idea that stupidity has increased is an illusion. The thing in the modern world is more that the tolerance for stupidity has decreased so we discover it more. The sad truth is also that each one of us believes in lots of stupid things but we are more interested in finding errors in other when in self improvement. Like Jesus said, "and why do you look at the speck in your brother’s eye, but do not consider the plank in your own eye?"