By my theory, Monty Python's "wide accountant sea" is the product of a civilization that is largely content with its lot in the world; but if a civilization finds it adequately entertaining to observe that I are serious cat and this are serious thread, then there are problems somewhere near the surface of that civilization, and the civilization is aware of them.
As an example: at least as far as I know, East Asian (Chinese, Japanese, and Korean) humor is much simpler than American and English; East Asians are more intelligent than Americans and Englishmen on average (at least as measured by IQ testing), but they have social stresses that are _much_ nearer to the surface.
I also doubt that low intelligence limits comprehension of refined humor. G.K. Chesterton thought that the English peasantry, who were at the least uneducated, were better at telling and at understanding jokes than their social betters; my own -- admittedly just anecdotal -- experience also seems to suggest no correlation between intelligence and sophistication of humor, but a high correlation between low social class and low education on the one hand, and good comedic style on the other.