Technology

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.

The only person liable here is the shooter.

On the very specific point of liability, while the shooter is the specific person that pulled the trigger, is there no liability for those that radicalised the person into turning into a shooter? If I was selling foodstuffs that poisoned people I'd be held to account by various regulatory bodies, yet pushing out material to poison people's minds goes for the most part unpunished. If a preacher at a local religious centre was advocating terrorism, they'd face charges.

The UK government has a whole ream of context about this: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/97976/prevent-strategy-review.pdf

Google's "common carrier" type of defence takes you only so far, as it's not a purely neutral party in terms, as it "recommends", not merely "delivers results", as @joe points out. That recommendation should come with some editorial responsibility.