Nonetheless, it still seems appropriate to me to view this change in labor market conditions as representing a decline in labor market slack. Intuitively, people who are non-employed, but not actively looking for work, are less likely to apply for any given job opening. Hence, the recent departures from the labor force imply that there is less downward pressure on wages.
Almost by definition, from an economic perspective, this means that there is less slack in the labor market. The rise in core inflation in the first part of the year is consistent with the view that labor market slack has fallen.