The original version of the new thriller featured a bloody shootout at a movie theatre but Fleischer re-filmed the scene after 12 cinema-goers were shot dead during a screening of The Dark Knight Rises in Aurora, Colorado last July (12).
Stone, who plays gangster's moll Grace Faraday in the crime drama, fully supported the decision and is adamant actors should encourage debate about the effect of movie violence on viewers.
She tells British magazine Live, ""It was right that director Reuben Fleischer re-shot a cinema shootout scene in Gangster Squad. It's difficult to make sense of something like the Aurora killings; it was all so horrific, I don't think any of us can.
""It's interesting being part of something that raises that kind of question because it's obviously relevant to the movie. People can draw what conclusions they like about the media's portrayal of violence and its effect on young people. We would all prefer not to have that discussion - but it is important we do.""
Stone's Gangster Squad co-star Ryan Gosling has also spoken out to back Fleischer's decision, insisting the director was brave to revise such an important part of the film: ""I was really proud of him because it really was the best sequence in the movie, without question. The day it (the massacre) happened he wouldn't even dream of keeping it in.""