Brescia striker Mario Balotelli has criticised the “small-minded” fans who shouted racist abuse at him on Sunday.
Castellini added they had recently signed a black player “and the whole of Verona applauded him”.
Balotelli, who has played 36 times for Italy and helped them reach the final of the 2012 European Championships, added: “Wake up you imbeciles, you are shambolic.
“When Mario scored a goal for Italy, and – I guarantee you – I will do so again, you are fine with that, aren’t you?”
Former Tottenham and Portsmouth midfielder Kevin-Prince Boateng, who also faced racist abuse when playing in Italy, says “nothing has changed” in football’s fight against racism.
Boateng, who now plays for Fiorentina, refused to continue playing a friendly for his AC Milan side against Pro Patria in January 2013 in protest at racist abuse from the terraces, with the match then abandoned.
“Six years later nothing has changed but we don’t give up,” he tweeted. “Let’s keep fighting all together against racism. #Notoracism.”
Watford report racist social media post
Premier League side Watford have reported racist abuse directed at defender Christian Kabasele to Hertfordshire Constabulary.
The 28-year-old Belgian defender had earlier flagged up the abusive post as part of Watford’s #BuzzOff campaign, which calls out discrimination on social media.
Watford wrote on Twitter that they “have already received a crime reference number from the Hate Crime team” and added they would “report back news of any action against the offender”.