Question

Read this line from the text:

My experience is that when Aunt Agatha wants you to do a thing you do it, or else you find yourself wondering why those fellows in the olden days made such a fuss when they had trouble with the Spanish Inquisition.

In comparing disappointing Aunt Agatha to the Spanish Inquisition, Bertie is using
hyperbole
malapropism
oxymoron
understatement

Answer 1

Understatement.

Answer 2

I agree. It's an Understatement.

Answer 3

@redskychicken