Ralph:
Actually, some feel that the words "There's a sucker born every minute" were put in P.T. Barnum's mouth by others who were trying to discredit the showman. Barnum's over-ballyhooed exhibits, some of which were outright fakes, were highly controversial in their time, with rival showmen greatly offended by Barnum's ability to make money hand over fist sometimes using basically nothing but false publicity. To make the public think that Barnum was contemptuous of the average man's intelligence would have been an attempt to get that average man angry enough with Barnum to stop going to his "museums" and circuses.
It did not work; Barnum thanked his detractors for the free publicity. His acts, exhibits and circuses kept right on going, most profitably.