https://townhall.com/columnists/johnhawkins/2011/08/23/7-reasons-why-liberals-are-incapable-of-understanding-the-world-n1082284
Even liberals who’ve accomplished a lot in their lives and have high IQs often say things on a regular basis that are stunningly, profoundly stupid and at odds with the way the world works. Modern liberalism has become so bereft of common sense and instinctively suicidal that America can only survive over the long haul by thwarting the liberal agenda. In fact, liberalism has become such a toxic and poisonous philosophy that most liberals wouldn’t behave differently if their goal were to deliberately destroy the country. So, how does liberalism cause well-meaning, intelligent liberals to get this way? Well, it starts with…
1) Liberalism creates a feedback loop. It is usually impossible for a non-liberal to change a liberal’s mind about political issues because liberalism works like so: only liberals are credible sources of information. How do you know someone’s liberal? He espouses liberal doctrine. So, no matter how plausible what you say may be, it will be ignored if you’re not a liberal and if you are a liberal, of course, you probably agree with liberal views. This sort of close-mindedness makes liberals nearly impervious to any information that might undermine their beliefs.