Presumably people who want to see their notes or get a birth debriefing feel something was not right with their labour/want things to be different next time.
But do you think that doctor/midwife will just say that they did all they could and that there's no way to predict how things could have happened? Are they going to say if we had done ABC instead of XYZ you/baby might have fared better? It seems like an exercise to justify that they gave you the best possible care? Cynical me, I know....