I generally agree that exit interviews are a trap and I also seek to avoid them unless it is with someone I trust, in which cases, they probably already know what the situation is and why I'm leaving anyway.
I did have one situation in an exit interview (with an HR person who absolutely did not like me and the feeling was completely mutual) where I offered advice not to hire a replacement for my role but to use my salary to hire two new people instead and promote another colleague to my old title. Even though this was the logical and obvious decision to make (my salary was roughly double what an entry-level person would have been paid and the team needed more headcount that it didn't have budget for, as well as a person ready to step up to a more senior title/role), I was still utterly shocked when the company actually listened to me and made the change. Good for them!
But I think a lot of people use an exit interview to vent and get all their bullshit with their old job on the table, and I imagine that can be really cathartic. Like the author of the piece, I'm usually not someone who will do any of that because of professional consequences that can come from that sort of thing, but that is also tied to the sorts of jobs I've had, where the communities around them tend to be fairly insular and where everyone talks to everyone and winds up working with everyone. At the job where they actually took my advice about hiring, I went to a competitor that was in the exact same building. Don't burn bridges when you're probably going to see people in the elevator or on the roof deck.
That is NOT the case for a lot of engineering roles.
If I worked for a contractor or vendor that then farmed me out to various clients (often large enterprise software companies with tens of thousands of employees and vendor roles), I would be a lot less concerned about the repercussions of speaking my mind in the exit interview with the vendor company, because the worst that will probably happen is that that company won't ever want to work with me again, but I can still go to a million other similar companies. Plus, the likelihood that you'll run into the same people again feels small when you are working on something more generalized than in a more focused area.
But even in a best case scenario, where a company actually wants to take your feedback into account, I agree with the author and largely don't see the value (for the employee) in sharing why they left.