I have to agree with this.
I had a similar experience when leaving. I was caught in a three way battle between my boss, his boss, and myself. I was the lowest ranked and ended up choosing to leave.
If you're considering "firing back" during an exit interview ask yourself the following questions:
1. Given the politics at play and the person I am speaking with what sort of outcome can I expect?
* There is no point in complaining if HR/higher up managers don't care or are complicit in the problems
2. Are my complaints grounded in fact or open to interpretation?
* Remember you are the one leaving. You will likely be blamed for the problems that led to you leaving. Make sure that anything you say is backed up with facts and difficult to spin (perception is reality).
3. How will my actions affect the rest of the team?
* You may very well get the person you are upset with reprimanded. Be mindful of how it will affect the larger team. In my case I did indeed get my direct supervisor moved off of the account and on to another team and I got his supervisor put on probation with another VP and HR sitting in on all team meetings. Unfortunately this meant much more scrutiny on the team as a whole. Some of the other members on the team who were valuable contacts of mine did not look on this kindly. And were understandably upset with me.
Remember most likely your actions will not get the person fired. It's easier to blame you for the problems and reprimand the individual at fault while attempting to diffuse the situation.
Managers will almost always be more likely to opt for a calm, predictable situation even with mediocre output from their employees over having to clean house, and find new talent. With the predictable approach they can work on the team over time and not further compound the upset that your leaving will cause.