Adrien Rabiot and Jonathan Rowe have been fined and transfer-listed after coming to blows following last Friday's defeat to Rennes.
"I ask you this. What happens if, at your workplace, two people, two employees, two workers, two lawyers, get into a fight?" De Zerbi told reporters in France.
"It was a bar fight, in front of the sporting director, in front of the coach, with a team-mate on the ground (Darryl Bakola, who had reportedly fainted).
'It's true that no teeth were broken during the fight, but it was a fight like I've never seen in all my years in football.
"For the first time in my career, I didn't know what to say or what to do. I've never seen anything like it. I come from the streets, I'm used to fights.
"But I've never seen anything like this. The club's bodyguards were trying to separate them. Normally they're supposed to protect us from others, not from ourselves."
De Zerbi also slammed Rabiot's mother and agent, Veronique Rabiot, for accusing the club of double standards after bringing in Mason Greenwood after he was cleared of domestic violence by an English court.
He continued: "The mother has forgotten two things. I decided to make him captain... and in one year, I gave her son more attention and affection than I did my own son.
"For Rabiot's mother to say that we gave Greenwood a second chance, that's crazy. We're talking about private life here.
"'It's not fair to talk about other people. We're talking about a workplace fight."