From the introductory part of The Decameron, in Pampinea's speech that inspires the seven young women initially to decamp to the countryside, she speaks of the atmosphere in their city of Florence at the time of the Black Death:
And if we quit the church, we see dead or sick folk carried about, or we see those, who for their crimes were of late condemned to exile by the outraged majesty of the public laws, but who now, in contempt of those laws, well knowing that their ministers are a prey to death or disease, have returned, and traverse the city in packs, making it hideous with their riotous antics; or else we see the refuse of the people, fostered on our blood, becchini, as they call themselves, who for our torment go prancing about here and there and everywhere, making mock of our miseries in scurrilous songs. Nor hear we aught but: Such and such are dead; or, Such and such are dying; and should hear dolorous wailing on every hand, were there but any to wail.
-- Rigg translation (emphasis mine)
E se di quinci usciamo, o veggiamo corpi morti o infermi trasportarsi da torno, o veggiamo coloro li quali per li loro difetti l'autorità delle publiche leggi già condannò a essilio, quasi quelle schernendo per ciò che sentono gli essecutori di quelle o morti o malati, con dispiacevoli impeti per la terra discorrere, o la feccia della nostra città, del nostro sangue riscaldata, chiamarsi becchini e in istrazio di noi andar cavalcando e discorrendo per tutto, con disoneste canzoni rimproverandoci i nostri danni; né altra cosa alcuna ci udiamo, se non: 'I cotali son morti' e 'Gli altrettali sono per morire'; e se ci fosse chi fargli, per tutto dolorosi pianti udiremmo.
-- Italian original (I've guessed at the corresponding phrase in bold)
The word becchini (left untranslated presumably for its specific cultural connotations) is the plural of becchino, meaning a gravedigger or cemetery worker. During a time of plague, I'd have thought these people would be some of the most unfortunate and overworked people in the city, to be pitied rather than scorned, but Pampinea refers to them in tones of disgust. Is this a kind of snobbery of a pampered aristocratic girl towards menial workers, or was there some reason to revile the becchini who were presumably doing the thankless and disgusting work of getting rid of dead bodies in a time of plague?
Why are the becchini spoken of in such a negative way?