What is it that makes some broken people to use their brokenness as a tool to hurt other people and others to rise above and become better people?

Several factors: some form of conditioning that led them to believe that way or be that way; it's what they have always known so it's what they do. There is always a choice to rise above the situation but some may not have the resources, support, education to change their point of view or not sure how to access these resources
or could be too far gone even when an opportunity has presented itself, due to fear of change, of the unknown, a mixture of anger, hatred, anxiety, substance abuse, mental health issues that can't easily be fixed.
Sometimes it just takes 1 person to make that difference to someone broken but some are completely too far gone or never met that person that could have possibly made that difference.
Just my thoughts, probably one for the psychology and sociology books.