The one point I don’t agree with: We have no clear way back.
There is a way back. As the shunning gets worse and worse, more and more people fall into the deplorables camp. Eventually, there won’t be anyone left on the left: they will all be excommunicated.
While everyone may eventually be shunned for one thing or another, it may take a long time for all of them to see that they have this in common with others. Some very bad things may happen in our country before people come to this realization.
However, when the author says there is no way back, I think the he is talking about the individual person who gets shunned, not a group of outsiders who have this in common. There is no forgiveness in the world of political correctness. There is no acceptable atonement, no matter how much the person grovels.