I'm not sure the "backwards" suggestion was meant to be taken quite so literally, my interpretation is that interrogative conversation, as opposed to narration, is the goal. Conversations, as opposed to narratives, do frequently go backwards without us even knowing about it or thinking about it, it probably happens more than you think.

"Hey I wrote this code"

"Why did you do that?"

"Because the frobnobbitz wasn't accounting for tribbles."

That's a conversation that runs backward. Anytime someone asked you 'why', and you answer, it's backwards. You don't have any control over what direction it is because the person asked you a question.

I'm really not sure but I suspect my own stories are less likely to paint an accurate picture of something than an interrogative conversation is. All humans have cognitive biases, so I wouldn't rule it out by thinking that I'm trying to tell the truth.

I've watched people practice true stories, many times, to a point that they become misleading. Not untrue, just misleading. (NB the author said "not entirely true".) Events are left out, motivations are made to look better intentioned than they were, etc. etc..

To be fair, I've seen plenty of lies made up on the spot too, so I'll refrain from defending the claim that one is more likely to be true than the other.

I still see value in placing conversation over narrative in a job interview.