
“The worst form of inequality is to try to make unequal things equal.”
Whilst a paraphrase this is based off of Aristotle's writings as Aristotle stated "For instance, it is thought that justice is equality, and so it is, though not for everybody but only for those who are equals; and it is thought that inequality is just, for so indeed it is, though not for everybody, but for those who are unequal" in https://www.loebclassics.com/view/aristotle-politics/1932/pb_LCL264.211.xml Politics, III. V. 8.
Misattributed
This first appears in 1974 in an explanation of Aristotle's politics in Time magazine, before being condensed to an epigram as "Aristotle's Axiom" in Peter's People (1979) by Laurence J. Peter