Parents who themselves did not recognize the existence of evil, never taught their children to be wary of evil. I didn't know that perverts existed until in my 40s. I never realized what homosexuals do until I was in my 40s. No one cautioned me about children being snatched off the street. The worst thing I ever heard of was probably contaminated Halloween candy. The newspapers were full of wars and deaths but I personally never encountered it until I was on my own in college.
I am old now. My parents are dead now. It was that way a long time ago. I had to learn about the existence of evil on my own. When one has experienced rape, theft, mugging, etc. then they learn that some humans act inhuman. They learn that one must imagine the vile acts that some people do, in order to protect oneself from them.
I never thought of my parents as "liberals." They wanted to raise their children in a nice place without fear. Liberals think that if they close their eyes to bad things (see no evil, hear no evil, think no evil – my mother actually did that once), then the world will be made into a better place.
But that's not true. Covering your eyes and denying evil does not make it go away.
As a society we need to address evil. We need some way to deal with people who fall on the extreme edge of the bell curve of human traits – the sociopaths, psychopaths.
End of rant.