Is there any reason why HN would be bound by EU laws, if it's not a European organization? What other countries laws should it be bound by, other than the ones it operates in?
Currently it may not be bound by them. But it could find itself in a situation where it matters - for example when working with / providing service to / getting service from another company in the EU which asks "so, are you GDPR compliant?" Given what HN does, that's not very likely though.