Kean was the victim of jeers and monkey chants by a section of the crowd at the Sardegna Arena and celebrated in front of the home fans after scoring in the 85th minute. Asked about the incident following the game, Bonucci said: "It was 50:50 -- Moise was wrong and the Curva was wrong."
Bonucci's comments drew widespread criticism with Raheem Sterling, Yaya Toure and Mario Balotelli among those to condemn the Juve defender. Bonucci later clarified his words had been "misunderstood" with an Instagram post.
"After the match, Bonucci expressed himself badly, but explained himself with that Instagram post," Allegri said in a news conference ahead of the Serie A clash with AC Milan which will be live on ESPN+ at 12 p.m.
Allegri was also criticised after he said Kean needed to "avoid certain gestures" -- and has moved to clarify he was not attempting to justify the abuse aimed at the 19-year-old.
"It is important to distinguish two things: racism needs to be fought and is never justified," Allegri added. "The other is the behaviour of the players during games because I'm not wanting to justify anything.
"For example, against Udinese [Kean] played a ridiculous backheel and that infuriated me because it was a lack of respect towards our opponents and they deserved respect. So racism is to be condemned and racists should never be allowed into stadiums.
"The behaviour on the field of every single Juventus player has got to be correct towards the opponents and the fans. Racism -- and this is my last word on the matter -- must be condemned and fought."
Meanwhile, Allegri said he is hopeful Cristiano Ronaldo will be fit to face Ajax in the Champions League quarterfinal first leg on Wednesday.
"[Ronaldo's] fine," he said. "We're five days away from game [against Ajax] and there are good signs. He is doing all he can to be involved and we hope to have him available."
Asked if Ronaldo will face Milan, Allegri replied: "Absolutely not."
Victory for Juve against the Rossoneri on Saturday followed by a defeat for Napoli at home to Genoa the following day would confirm an eighth consecutive Serie A title.
Information from ESPN FC's Italy correspondent Ben Gladwell was used in this report.