I think it would be quite sensible to disallow anonymous comments on your blog as anonymity tends to bring the worst out in people.

Experience shows that commenters who hide behind anonymity often use weblogs as a vehicle to publish foul, inappropriate, and sometimes illegal content.
http://www.dba-oracle.com/oracle_news/2006_04_18_no_anonymous_blog_comments.htm

“Eli Rabett” claims to be a university professor at a research institution. If this were true, and not just a façade, his frequently derogatory comments would bring his position into disrepute. One way of reducing inflammatory or odious comments is to request identification which would raise the shame level. All the same, even this safeguard would not prevent comparable forms of harassment by well-known people who appear to be impervious to ignominy.

Obnoxious perhaps, but it is essentially the same criticism he has made many times before. Assuming Eli’s blog is accurate, I don’t see how it can be interpreted as a threat, or as particularly disturbing, or even why you would think it deserves a response.

But it is your lemonade stand