If self-styled public choice theorists took things like this more seriously, I think people would take them more seriously.
When was the last time you heard a politician give a stump speech promoting deficit spending? Both parties right now are taking distinctly anti-Keynesian positions - either they're promoting spending cuts and tax increases or pure spending cuts.
I take the point of public choice theory seriously. I think we do need to explain political behavior on the basis of the incentives of politicians (chief among them being the incentive to get re-elected). I wish self-styled public choice theorists would take public choice theory more seriously.