I don't either
I'm not sure how they are commenting, because it doesn't appear that they are registered, and I need to check those settings.
Some of them have been uses as trackbacks, they will post a comment on another site with a link to that comment.
My other thought, since this situation started years ago, that they might be messages of some kind. Some of them have been quite cryptic.
The IP resolves to Guangzhou China.
I'm leaving this one up for now, but will either delete it or delete the text soon. All others will be deleted.