There are two very common theories about why the experts should not be trusted. The first one is that economists are rich, they're white, they're male and have self-serving bias. Second story: Economists are ultra conservative Republicans who think all these crazy things no sane person would think. David Frum says there's a specific test for why you think that the experts are not to be trusted. He says it can't work because the typical economist is a moderate Democrat.
Bryan Caplan, of George Mason University and blogger at EconLog, talks about his book, The Myth of the Rational Voter: Why Democracies Choose Bad Policies. Caplan argues that democracies work well in giving voters what they want but unfortunately, what voters want isn't particularly wise, especially when it comes to economic policy. He outlines a series of systematic biases we often have on economic topics and explains why we have little or no incentive to improve our understanding of the world and vote wisely. So, it's not special interests that are messing things up but the very incentives that lie at the heart of a vote-based system. This is a disturbing and provocative lens for viewing political outcomes.