Now, if that's right, one might wonder why such a tainted phrase is so immensely popular, especially on the left. But then, many Germans like "quoting" Churchill's ostensible insight "I don't believe any statistic that I have not fabricated myself", despite the phrase probably having been put in Churchill's mouth by the Nazis (link in German). People don't know about these things.
What I find more surprising is the phrase's popularity despite its lack of qualities that one might think make for a popular phrase, such as wit, insight or alliterations. What's more, it often doesn't seem to fit particularly well. While "dismal" is just the word to describe an Introduction to Macroeconomics lecture, the use in other contexts often seems a little laboured. Economists failed to predict the housing bust? Dismal! Lab experiments falsify Savage axioms? Dismal! Econ students can't get laid? Dismal! That poor adjective is allocated more work than it was cut out for.
We clearly need more derogatory terms for economics. I hence propose that economics is Farting by Numbers. While I'm at it, sociology is Compassion with Significance Tests and Ethnology is Tourismplus. Spread the word, oh readers! Or come up with your own. It's not that hard.