I have been thinking about this for a while, and came to the conclusion that the main weakness of progressivism is its arrogance. A progressive simply thinks that she is more educated, virtuous or simply better than others. This manifests subtly, from "helping poor immigrants", to not so subtle implementations, like knowing better what Google queries you actually meant to type, to censoring "fake news", because people do not have the faculty to decide for themselves, to downright auto-correction of people's speech. A progressive copes with this implied superiority by casting it as her goodness.
My take on the situation is that as a movement and political ideology "Progressivism" is steeped in a sense of righteousness. I very much sense progressives have internalized the notion that what they are fighting for is so obviously good, correct, and just that anyone who opposes such self-evidently virtuous things must either be 1) brainwashed by malevolent forces (Fox news, misinformation, propaganda, internalized oppression) or 2) constitutionally flawed people who cannot be redeemed and must be fought against ("Deplorables", fascists, nazis, racists, etc).
One of the best films on this subject is Dogville by Lars von Trier https://en.wikipedia.org/wiki/Dogville , with Grace as its main character.