I will put this another way:
If you cannot see evil in yourself, you cannot see it in others; conversely, if you cannot see it in others, you have no ways of seeing it in yourself.
The motion of the world consists in expanding and contracting, expanding and contracting. Goodness is expansion, evil is contraction. Logically, then, a blindness to evil consists in a blindness both to contraction, and to a lack of expansion. It means blindness to precisely what is holding you back.
If we posit that the demonic is that which contains you, punishes you, makes you smaller, then a blindness to the demonic means you have no hope of controlling your own life, and will therefore need someone else to do it for you.
I have in mind Sybaritic Leftists, but there is a clear continuum from rejecting Good and Evil in principle, to embracing the latter. I see references to this throughout the culture of the last 150 years.
These are some of the issues I tried to deal with in my iteration of the Grand Inquisitor. This here is slightly different language.
I will reiterate that I am a Liberal. I want more freedom for everyone, to be and do whatever makes them happier, whatever best unleashed their creative energies, and creative bliss. I simply REFUSE to be stupid, to believe things out of habit, or because they are repeated around me constantly. All of us were born with consciences and minds, with the expectation we use them. There is no better system of government than our own, in principle, even if culturally we have fallen far short of the moral courage and honesty needed to operate it properly.