David Horowitz does a fine job of reviewing and explaining the sickness that is the liberal mindset.
In this short, revealing essay, one of his comments is profound:
The strength of the virus [liberalism] derives from the meaning it supplies to meaningless lives, and the consequent good feelings — intoxicated feelings of virtue and self-righteousness — experienced by the devoted.
And one of his quotations is equally significant:
“The virus [liberalism] totally blocks the person from the ability to access, let alone comprehend, any facts and evidence that contradict his or her beliefs. Mountains of data have zero effect on already established views, simply because the person flatly rejects considering reading anything that would go against their ‘truth’. The person is terrified to look beyond his established viewpoint. They behave like the Church at the times of Galileo. They refuse to look through the telescope.”
Read the entire diagnosis of this insanity here.