The logical extreme of this statement is that @mholt shouldn't post a link to any website unless that link is specifically tailored to the average reader of the site he's posting to. That, or Hacker News is special among all websites @mholt could post to.
I don't think that's fair. I also don't see the defensiveness you see - instead, I see @mholt explaining his website's strategy for the benefit of your understanding (as well as that of any future readers). The alternative to which would be not responding to your feedback at all, as he already has sound reasoning not to incorporate your specific suggestion (which we know because he explained it).
It's important to read into the best possible interpretation of a comment and respond to that, assuming good faith, especially on communities like this one. Otherwise we begin to assume everyone is attacking or defending.