Maybe I'm missing the ToS where copyright is assigned to HN, but I'm going to guess that a simple DMCA notice to HN would have all your comments deleted quite expediently.
That's a bit questionable if you fight it as they may be considered to have an implied license due to the fact that you posted it here to begin with. It was never really contemplated in terms of removing content placed there by its author.
You might also get put into a Chilling Effects database, assuming HN contributes to that (I honestly don't know, but it seems plausible). These are significantly less public than they were prior to the Google removal, though.
Have you ever posted a joke that might offend?
Have you ever linked to one or more past projects?
Are you aware that you can not delete your account or your posts?