This is literally one of the topics covered in the article and the author advocates for the same solution, documenting the alternative in the error/deprecation message...
1. That gives the appearance of a user who hasn't read the article
2. Even if the user did read the article I'm not sure what their comment adds to discussion of the article. For comparison, imagine participating in a conversation with a few friends in real life, friend X says "It's a good idea to write tests for your code," then friend Y replies "It's a good idea to write tests for your code." Usually the way people discuss things is to reply or offer addendums to the original idea. It's not a rule, it's just good conversation.
The article in question is usually not the topic of conversation on HN. It is better to consider it to be the launching point for the conversation. Some will discuss the article, certainly, but you can expect the conversation to branch out very quickly to related items (especially if those items are mentioned in the article). While it's probably not a good idea to discuss the plight of African elephants in these threads, drawing attention to a minor, but specific point in the article is perfectly cromulent.
In this case, the post has value. It does two things. First, it draws attention to a subtopic that was only an aside in the article. (One I happened to miss the first read-through.) Second, the phrasing in the article is somewhat general and vague about this, and the post is relatively more specific and direct.
And in the case where people don't read the article and just read the headline, many comments have nothing to do with the article, and end up discussing a less interesting misconception of the submitted article's title/headline.
It's great to be generous with our interpretations of comments here on HN. But I would like to push for a higher standard of discussion, which has always been the draw of this community, particularly for technical articles (and this is actually a high quality technical article!). So I don't think I'll ever be happy being generous to a low value comment that re-states an opinion from the submitted article without adding anything or even without adding much.