I vouched for this comment. Perhaps it's not exactly what the question is asking for but is well-formulated (if a bit subjective), and comes from a newly-registered user (welcome to HN!), so I don't think it deserves to be "dead."
https://news.ycombinator.com/newsguidelines.html
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For this reason, I don't think there is any obvious parallel to vouching that you're trying to draw here. However, perhaps I am wrong. Can you point to a comment by @dang that would substantiate your opinion?