I have immensely enjoyed Roger Pulvers' recent articles on Japanese humor. I above all agree that the best joke is always on yourself. Humor must have a lot to do with the ability to laugh or smile at yourself, especially in a troubled situation. Therefore, I usually do not find humor in ethnic jokes.
But let me add something. Pulvers says the Japanese do not tell jokes at the expense of their neighbors, the Koreans and Chinese. I think that's because some of us Japanese feel inhibited from making fun of them because of the tragic history lying between them and us. The atrocities Japan committed during its colonial days have left some of us with a guilty conscience. It is sad actually.
It is too bad that Pulvers did not mention rakugo comic storytelling. Rakugo is representative of the harmless fun that Pulvers says is characteristic of Japanese humor. Rakugo was once thought to be old-fashioned, but now it is no less popular than the Osaka-based owarai laugh culture.