The better question to ask is the left in the US liberal in the old sense of the word or are they totalitarians.
Liberals believe that they are much smarter than you.
Since they are smarter than you they think they should run things.
Liberals believe that their plans for you are for your own good, because they have a grand vision of how things should be.
If you balk and refuse to go along, you are stupid and like an unruly child, you must be forced to comply even if they have to kill you. This will be rationalized as "He was just too stubborn and hateful to see the light and it was his own fault"
The only difference between liberals and Stalin, Mao, Pol Pot, Idi Amin dada, and Saddam Insane is that they haven't acquired total power and still have to keep the mask in place.