The author thinks it's because those people are more stressed. I think it's because those people are sending a message to their boss that they are a pushover.
https://www.linkedin.com/pulse/artic...d-for-businessThat totals $52.4 billion workers just gave away. Essentially, rather than take the time they were due off, millions of American workers said to their bosses, “Hey, no problem, we’ll work for free.”