When you start to explain Quantum Theory to people - I find, anyway - they (usually) glaze over and stop trying to understand. It would appear that there is a genuine barrier between the concept and the understanding of the concept.
The same thing appears to be true with MPs and their expenses. They just don't get it. They REALLY just don't get it. Every other person in the UK thinks they are a pack of vultures dragging their rotten bits of flesh of the decaying carcass that is our "democratic" system. They think it is OK.
Shoot them all.