There's a lot of reference to research that the authors claim show that stock buybacks are bad and terrible, but no description or quantification of how exactly

There's a lot of reference to research that the authors claim show that stock buybacks are bad and terrible, but no description or quantification of how exactly their research showed this. The closest I can see is "According to our research, when trillions of dollars of corporate cash are extracted from companies through buybacks, on top of dividends, the result is a dramatic concentration of income among the richest American households and the destruction of middle-class employment opportunities." To me, this is phrased the way politicians phrase descriptions of studies, stats, or findings that they are wildly misusing.