As an EU-based engineer, you wouldn't do this, it's a massive GDPR violation (failure to notify data subjects of data processing), which does actually have extraterritoriality, although I somehow doubt that the information commissioners are going to be coming after OP.
Processing comments on a forum being a violation of the GDPR? That's crazy, the OP is neither the data controller (HN is) nor a data processor on behalf of the controller. If you post your data in public, it's not a GDPR violation for people to use it for things.
