Why is it accurate to say that "the Pardoner's tale" is filled with irony

The irony in The Pardoners tale is that he preaches against the sin of avarice - "the love f money is the root of all evil" - when in fact he is guilty of this sin. he makes a living selling useless artifacts to peasants who believe that this will absolve their sins

The irony is that he preaches against the sins of avarice