The “what happened?” part of the title implies that there has been a shift in how comfortable men are with hugging. But the study doesn’t show that there has been. Per the article:
We may here be seeing an age effect, rather than a generational effect: younger adults are generally much more likely to cry and therefore worry more about whether they should or should not.
This is my suspicion. I’ve become more comfortable expressing emotions and being myself as I get older. Is that the trend and the explanation for younger men not being as comfortable demonstrating their emotions? The study doesn’t tell us.