The left did not lose touch with the working class. The left is what started and continue this populist movement.(Bernie Sanders in the 2016 election cycle; AOC; and the socialist/communist parties that go out and encourage organization to fight for worker rights)
Trump (a billionaire who spent his career exploiting workers) acted like he was picking up the baton to fight for worker rights after he saw people's reaction to Bernie Sanders losing the primary against Clinton. Unfortunately, workers like these in the steel industry WERE tricked into thinking that Donald was gonna support their professional cause, this is objective. Now many people are calling them stupid because to many other Americans, this was the obvious outcome due to Donald's track record both as a businessman and as President. For some reason, these steel workers were blind to it all...
I find Michael Moore neither smug nor obnoxious. You and others interpret Michael Moore's messages as being smug and/or obnoxious, but there are a lot of other people who listen to his messages without animosity. This pattern is also true for Joe Rogan. I am certain that there are people who interpret his message as being smug or obnoxious.
The reality is the nature of conversation is complicated: the result relies on how information is produced by the speaker AND how it is interpreted by the listener. So the root of the problem is twofold. It's not just that people are having a hard time speaking to those outside their circle. It is also that people are having a hard time listening to those outside their circle. The blame is not on the left or the right, it's on both. Both exist in their own circle jerk, and neither groups are able to talk and listen to each other.
I think the fact that we all aligned once this CEO died reveals why this division is important those in power (Top 1%, billionaires, and multi-millionaires). If we did all team up, these people in power would be in trouble. Instead, we are being divided into two sides that cannot even communicate with each other. And because of that, we are being conquered by these oligarchs and we are too busy fighting each other to know what's going on.