That is not necessarily all you need to know about why liberals do what they do but it is essential. One cannot understand liberals without understanding their fundamental, unrelenting quarrel with the first and second commandments.
As God they would opportunistically expropriate godlike qualities of infallibility, omniscience, benevolence and omnipotence.
Those who oppose the benevolence of these gods must be possessed of antipodal character and motivations. Hence, those who disagree cannot be well-intentioned but evil, not omniscient but stupid, not infallible but always wrong.
Because they are not God but human, leftists create their own epistemology which has varied forms but the best single place to look is at The Frankfurt School which lays down a catechism the essence of which is to destroy the Judeo-Christian insight enriched by our experience of the Enlightenment and substitute a nihilistic philosophy of "critical thinking" which permits the God player to conveniently dismiss any evidence which might stand in the way of coming to any conclusion he wishes.
Freed of logic, the next step is to free the leftist God player of morality. Look to Alinsky's Rules for Radicals as a primer of immorality and political dirty tricks.
… Because they would be God
