He probably didn't know what "snake oil" was, but I wouldn't put it past him to have been familiar with the term (he loved playing with idioms) and set the reporter up. If the reporter had defined it differently--"Snake oil is a fake panacea"--he'd have had a smart-ass response to that instead. One way or the other, he'd have turned it to his advantage.
The only reason he admits to being a snake oil salesman here is because he didn't really understand the question, even though most of his products are snake oil!
