Question

"again we hear it alleged that the moral corruption worked by jazz is vastly more calamitous than was the material havoc wrought by the World war." the above statement contains an example of which rhetorical device

Answer 1

The above statement contains an example of the rhetorical device known as irony.
Don't you think it is quite ironic that many people believe that the influences of jazz music and era of the 1920s are far more devastating that the disaster that the WWI brought to a nation?

Answer 2

There are two possible answers to this question:

The first one would be allusion. The passage uses allusion because it references the World War. Allusion occurs when an author references an object of an unrelated context in an indirect way.

The second option would be hyperbole. Hyperbole happens when the author makes an exaggerated claim that is not meant to be taken literally. In this case, by saying that jazz has caused more destruction that the World War, the author is clearly exaggerating for dramatic effect.