Sure, but the GGP comment said they would be giving you a bad reference anyway, while the GP comment (and the article) made the point that sometimes they will o

Sure, but the GGP comment said they would be giving you a bad reference anyway, while the GP comment (and the article) made the point that sometimes they will only give you a bad reference if you manage to offend them during the exit interview. 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.