The Secret History of the Dismal Science - Library of Economics and Liberty

How the Dismal Science Got Its Name

Quoting:

Almost everyone knows that it was given this description by Thomas Carlyle (1894), who was inspired to coin the phrase by T. R. Malthus's gloomy prediction that population would always grow faster than food, dooming mankind to unending poverty and hardship.
While this story is well-known, it is also wrong, so wrong that it is hard to imagine a story that is farther from the truth. At the most trivial level, Carlyle's target was not Malthus, but economists such as John Stuart Mill, who argued that it was institutions, not race, that explained why some nations were rich and others poor. Carlyle attacked Mill, not for supporting Malthus's predictions about the dire consequences of population growth, but for supporting the emancipation of slaves. It was this fact—that economics assumed that people were basically all the same, and thus all entitled to liberty—that led Carlyle to label economics "the dismal science."
Carlyle was not alone in denouncing economics for making its radical claims about the equality of all men [and women].

Emphasis is mine. The words by David Levy and Sandra Peart. And Mill remains correct today: about the nature of humanity, institutions, and the economics discipline.