If they can help to deanonymize you, they must contain something personal. Writing pattern are pretty personal, certain spelling errors too, or the choose of words.

Absolutely anything relating to an anonymous person could help deanonymization, so that implies that anything relating to any person is personal data. Is that the GDPR’s position?

From ico.org.uk: “ It is important to note that opinions and inferences are also personal data, maybe special category data, if they directly or indirectly relate to that individual”

From gdpr-info.eu: “ Subjective information such as opinions, judgements or estimates can be personal data.”

So yes. HN is in violation of the GDPR. I had already filed a complaint about this policy at my local GDPR authority.

If you are posting public comments, then these comments are available publicly... like, what did you expect!?

Yes they are. The GDPR doesn’t say you can’t post it.

Under article 17 of the GDPR, EU citizens have the right to be forgotten, in which case this data needs to be deleted.

Well, the username attached to them would surely be.