If you look closely, you'll notice a lot of the language used by the left is straight from European playbooks. What I think tends to happen is that European opinionators make known their stance, and then the American left, being very fond of everything European, simply pick it up and run with it as if it were the word of God.
...For instance, calling Trump "authoritarian" is totally European rooted, because in Europe, right wing means more government control, where as in America, right wing means less government -- It's the total opposite. So what we have is misinformation being fed to the American left, and they just run with it anyways, not even caring that it makes no logical sense... Realistically, the left is far more in line with Authoritarianism in the United States based on their desire for restrictions on speech, and governmental overreach in general.
Other examples include the use of the word "nationalist". A term that makes no sense In the United States, but makes total sense in Europe where many tiny countries live interdependently with each other... In Europe, nationalism is an actual problem, because small countries rely on one another for resources, but here in America, it really makes no sense.
These are just two examples of European influence/control of the American left.