At some place called Market Watch. Perhaps it isn't a leftwing source, I don't know. I've never heard of it. I just had to chuckle when it came across my desk. I have a gut feeling, though, that the author isn't exactly hostile toward a progressive POV. The whole point is 'Labor Day weekend shows America is getting nice.'
How did it show this? Because liberal views and ideals and individuals were promoted, and those who aren't liberal were trashed, hashed, banned and in other ways shown the door.
It's the 'of course liberals, duh' attitude that drove many a voter into the arms of Donald Trump in 2016. It appears those clever liberals haven't figured it out yet.