He made vicious fun of the English bourgeoisie in plays such as The Importance of Being Earnest . The same bourgeoisie packed London houses and made him a fortune without realizing the joke was on them.
The viewers of the film didn't realize that they were being made fun of. 
mnli hypothesis: The viewers of the film didn't realize that they were being made fun of.  premise: He made vicious fun of the English bourgeoisie in plays such as The Importance of Being Earnest . The same bourgeoisie packed London houses and made him a fortune without realizing the joke was on them.