Who would be the right one to sue? Reddit is hosting it, but they are using admins to keep discussion civil and legal; the admins of PCM are most likely not employed by Reddit, but are they responsible for users egging each other on? At what point is a mod responsible for users using “free speech” to instigate a crime? They should have picked a few posts and users and held them accountable instead of going for the platform. People will keep radicalizing themselves in social media bubbles, in particular when those bubbles are not visible to the public. Muting discussion on a platform will just make them go elsewhere or create their own. The better approach would be to expose them to different views and critique of what they are saying.