Silly optimist, Russell. Poverty is a useful way of keeping people scared, enervated and grateful. It's not a product of stupidity at all. We got a little shared prosperity going in postwar 20th-century America and look what happened: civil rights, equal rights, asking of questions, general flipping-off of Mr. Dithers. Had to be stopped. Easiest way: cut public services. It made everyone scared, enervated and grateful again. Couldn't quite put the ideas back in the bottle again but it went a long way to tamp things down, no?
I'm guessing he meant stupidity in the megasense: failure to grasp that huge inequalities of wealth, health, education, monopolies of natural resources and so on are not just bad for the poor but will be bad in the long run for the species and the planet itself. I agree with your point, though. Republicans are not being stupid in the short run when they run up deficits and cut taxes on themselves (and services for everybody else.) This is their personal/party get rich quick plan and the suckers fall for it every time. Keep your government hands off my Medicare, and so on.