Author expects interviewees to "tell you what you want to hear", recommends requiring their W-2, admits that companies oversell themselves too, but doesn't appear to offer the interviewees the same insight into company data, expecting them instead to "probe for related information and same truths 20 different ways".
Maybe I'm just a bit cynical (or not familiar with how sales works), but it seems that this is a mechanism to give an interviewer more cards.
That said, it is an article from an interviewer's perspective, so I suppose that's a bit expected.