As per community consensus on Hot Network Question Silly Title Comment Sanity and Is commenting about funny title wording considered off-topic? - off-topic / too chatty comments about humorous question titles are to be deleted, and users are requested to flag them for moderator attention.
I've recently flagged this old question: My head keeps falling off. What can I do? - with a custom comment and a link to the first meta post I posted above, so that most of its comments can be purged, but got declined with the following reason:
This question is 5 years old and isn't hurting anybody. We're trying to reduce noise going forward, not rewrite history.
I've been flagging many of these types of comments as I notice them. Most of the flags are marked 'helpful' and the comments usually get deleted. This is the first time I've been declined with this as the reason.
We're trying to reduce noise on all questions and answers, regardless of age. Also, most of that question's comments are about the title, burying the actual on-topic comments about the question.
As per the Meta SE FAQ post, How do comments work? (emphasis mine):
When should comments be deleted?
Comments are temporary "Post-It" notes left on a question or answer. You should not expect them to be around forever: Once a clarification has been made, an edit added to the post to include new information or the issue in the comment is otherwise resolved, it is subject to deletion. In reality, many obsolete or chatty comments remain untouched due to the high volume of comments posted, but this does not mean that they can't or shouldn't be deleted in the future.
I believe that regardless of "history", those comments should have been deleted.