Personally, I think that it is a miracle that liberalism even took root in Western countries, because historically, Western cultures killed off the offspring of their people who were deemed pathetic. Do you think for one moment that the Spartans permitted pathetic people to exist in their society? The Norse? The Germanic tribes? Where the white liberals come from, I have no idea—there is no evolutionary basis for it whatsoever.
My theory is that liberalism took root specifically because of advanced technology and the prosperity it brings. When people struggle to survive, no one would tolerate liberals. Now, technology provides plenty, protects us from brutish reality, and gives us the luxury to entertain these nonsensical ideas. Further, when survival is no longer at issue, employing common sense makes people seem judgemental and “mean”. Those who go on flights of fancy seem reasonable because it sounds good and we are insulated from the consequences of our actions.