Martin luther king jr. and mahatma gandhi led large groups of people in protests against injustice. according to information in your text about the process of deindividuation, why is it that these groups did not behave violently?

No model for violence--deindividuation suggests a person losing their identity to fall to group-think and crowd behavior. 

With a model of non-violence, crowds followed the model provided. If members of those movements were deindividuating from their 'normal' behavior they were doing so in a non-violent way to follow the crowd. Additionally, these movements were focused on the individual with both leaders caring deeply for the stories and lives of those around them.