How does any of what you said matter? Even if you think making $140K isn't upper middle class, the research still shows more people are going from $90k to $140k than those who are going from $90k to $40k. It still shows that more people in the middle class, however you define it, are going up in income than are going down.
These categories are just arbitrary lines used to make it easier for people to identify and understand the insights analysts are able to pull from the data. And however you slice it, the data shows a story of improvement. Not as much improvement as I'd like to say, but improvement overall. We have been seeing the same trend for 30+ years.
What this story doesn't show is the dark side of an otherwise good development. Most people don't really notice day-to-day how much better off the 1% are because there are so few of them (by definition). But when a growing number of people see 30%+ of people around them living much better lives, they begin to notice.