HN Violates the GDPR

I care about GDPR because my employer has a physical presence in multiple EU countries. However, a US based company with no physical presence wouldn't really care. Wouldn't it be nice if they had to.

There are a lot of things in GDPR that I agree with and anyone who follows it in spirit is going to get my business over someone who does not, and that is something all of us can do. But beyond that, I'd recommend that OP remember the classic saying "You catch more flies with honey than you do with vinegar" and maybe ask the moderators nicely to remove whatever past comments are irking him.

IANAL

My armchair argument would be that when you sign up to post on a public forum, you should have every expectation that your posts will remain visible. Expecting otherwise would be rather like publishing a book before invoking GDPR to 'un-publish' it and demanding to have all the sold copies destroyed several months after release simply because your name is on the cover.

The expectation of content remaining public is also explicitly stated in HN's terms, along with a pretty broad-ranging agreement to allow them to use the content you upload. Thus arguably HN has a contractual right to continue publishing the content, as allowed for under art 6.1(b).

GDPR Article 6: "Processing shall be legal if and only if to the extent that at least one of the following applies ... (b) processing is necessary for the performance of a contract to which the data subject is party ..."

Sure, if I can identify the natural person from the name yummybear then yummybear is personal information.

But HN simply can't do that for most accounts, and so for most people their username isn't personal data.