The Left seeks to adjust the world to conform to their world view.
With what you said (which is quite true) I think it boils down to this:
Leftists think Utopia is achievable, humans are perfectible, and if they aren’t perfect, someone somewhere did something wrong to explain it and that evil doesn’t exist.
Conservatives think Utopia is unachievable, humans can never be perfected, and if they aren’t perfect in a bad way, they bear personal responsibility for that, and we must have safeguards against them because evil does exist