I read it as a reasonable and slightly humorous way to acknowledge that the author is a human being and may have been (justifiably?) in a bad mood writing the p

I read it as a reasonable and slightly humorous way to acknowledge that the author is a human being and may have been (justifiably?) in a bad mood writing the post because lack of sleep does that. No idea of how sensible that suggestion is or isn't in this case but didn't really think it was derogatory. A human being is not a machine. Sanity-sleep might be a better term for it but nobody uses that whereas beauty-sleep is in common, albeit ironic, usage. Let's all take our sleep seriously, yeah? :-)