Earlier quoted context omitted.
> If you are both professionals, it's a cathartic experience that supports your remaining coworkers. If they are not professional, they weren't going to give you a good reference anyway. It seems to me that the author is suggesting a third type of person: one who is professional until they're criticized.
then they are not professional, taking constructive criticism come with being being professional
Some people are just insecure and always get offended by constructive criticism, some people have poor communication skills and think they are "just being honest and constructive" while actually being very offensive (we probably all know a few coworkers like this) and sometimes the person doing the exit interview has just had the worst day of their lives. Bland platitudes in the exit interview will almost never hurt but candid feedback can definitely go sideways very quick. Game theory says it's better to play it safe.