I think part of it is that they were kind of told they were doing something morally good by helping make the case against prisons and advancing a certain versio

I think part of it is that they were kind of told they were doing something morally good by helping make the case against prisons and advancing a certain version of social justice. One takeaway could be that social justice ideology can be used to perpetrate horrific things, as long as the ends appear to justify the means.