That's the title of the chapter of Gordon Tullock's book (The Organization of Inquiry) in which this quotation appears:
A friend of mine in physics once said that he could not understand the social sciences. “You’re always arguing,” he continued. He was, although I do not think he realized it, quite an acute social critic and had neatly placed his hand on one of the major distinctions between the social and natural sciences. The social studies are dominated by arguments, while arguments are much less common in the “exact sciences.” Arguments, sometimes bitter and protracted, do occur in the natural sciences, but they occupy much less of the investigator’s time. Even a casual inspection of a journal in the natural sciences and one in the social sciences will indicate the great difference in the proportion of space devoted to disputation in the two fields. The social scientist must devote much of his time and considerable energy in “convincing” people, while the natural scientist can give much less energy to this matter. Further, arguments in the natural sciences normally are settled by some further advance in knowledge which makes one point of view or the other (sometimes both) obsolete. This is much less common in the social sciences. The fallacious defenses of tariffs which were invented in the fifteenth and sixteenth centuries still appear with monotonous regularity in the literature.Tullock wrote this in 1966. The Logic of Collective Action came out in 1965; "rent seeking" -- which this describes -- was coined in 1974.
The explanation of this phenomenon is fairly simple. While almost everyone would, in the long run, benefit from the removal of tariffs, and the raising of tariffs is a blow to the welfare of almost everyone, there are, at any given time, minorities which can be hurt by the reduction of specific tariffs and helped by the increase of others. Now the benefits of the repeal of a given tariff are likely to be dispersed over the whole population, while the injury will be concentrated in a small group. Although the benefit will be much greater in total than the injury, it is slight for any individual. The group which suffers concentrated injury, however, is likely to try to convince the majority that really they gain nothing and to hire economists for this purpose. Since there are always some such groups, there will always be economists who have been hired for this purpose.
Bottom Line: Incentives matter.