Is it harder, are you sure? There isn’t a button, but HN also doesn’t try to talk you out of it.

Unlike Facebook, Hacker News has no Personally Identifiable Information on you, didn’t ask for any, and isn’t trying to gather any. Email address might be the lone exception, but you can use any throwaway email you want. So you might have chosen to share some, but other than email, HN has no way to index it or even know that it’s personal to you. There’s no network, no photos, no credit cards. There are no ads that HN is selling your PII to. Unlike FB, HN doesn’t do any EU specific business or target EU residents in any way, so combined with the complete lack of PII, it’s very likely GDPR does not apply to HN. Comments aren’t enough, they don’t act as a catalog of PII.

That said, have you tried emailing HN to see if they’ll happily delete your comments? If there was a legitimate problem that you needed to erase, if your identity become known against your will, I’d bet the mods here would be happy to help you.