… is from page 165 of Thomas Sowell’s November 1st, 1995, column titled “The Benefits And Hypocrisy Of Playing The Slavery Card,” as this column is reprinted (and retitled “The Slavery Card”) in Sowell’s 1999 collection Barbarians Inside the Gates:
While the Western world was just as guilty as other civilizations when it came to enslaving people for thousands of years, it was unique only in finally deciding that the whole institution was immoral and should be ended.