I think it's pretty clear from context that it was a paraphrase, especially since the phrase "must have been X of this particular type" is clearly a template phrase. It's a fairly common English construction; "oh won't someone please think of the children" in quotes as a response to an article doesn't imply that the article linked actually contains that phrase.

However at least the comments here are no stupider than the HN norm, when it comes to non-programming scientific topics. The frontpage right now contains two pseudoscientific bullshit stories: something from The Atlantic about "Toxins That Threaten Our Brains" (that's a verbatim quote), and this run-of-the-mill evo-psych bullshit.