Human Nature.
This is the issue and is what the left fears the most.
They have no Faith in Man because they have no Faith in themselves. Having rejected Faith in God, they are left with placing their trust in Man to control Human Nature.
“History Repeating”
https://www.youtube.com/watch?v=yzLT6_TQmq8
It’s not about controlling human nature. We do it all the time using the guard rails of punishment to keep it within broad bounds. What they think can be done is to CHANGE human nature, bringing about the New Man. We are not perfectible, but there’s always someone thinking they can legislate our innate drives away.