… is from page 213 of the 1975 collection of some of Harry Johnson‘s essays, On Economics and Society; specifically, it’s from Johnson’s 1973 essay “Some Microeconomic Observations on Income and Wealth Inequalities”:
These misperceptions [of the sources and significance] of the problem [of income inequality] lead both to an exaggerated and naive concept of the importance and urgency of inequality, reflected in the use of such superficial and irrelevant statistics as “the top x percent of the population receives ax percent of the income,” where x is a small fraction and a a sufficiently large integer to convey the impression of obscenity; and to the recommendation of superficial and analytically weakly-based or insupported policies for remedying inequality by taking large sums from those who have currently high incomes and giving them to those who have not.