What it really is though is unpolitic. Especially in the USA, suggesting that something can wait, or that the morale boost from working less will end up in more productivity angers a lot of people.
"They're out of their minds! They suggest that it can wait and the morale boost from working less will end up in more productivity... Blasphemy! They're just lazy! I've worked 90 hours a week for 7 years, and because of that I'm ill and borderline insane, but IT'S WORTH IT, I'M PRODUCTIVE!!! Sure, I'm chronically stressed and made 3 burn-outs, but I get stuff DONE. Those no-goods can't understand what it's like. They don't understand what sacrifice means! Grumble."
That being said, this doesn't mean Americans aren't the most productive overall, since Americans do work insanely long hours compared to Europeans.