The pitch limitations have initially been put into the flight control laws because while such high attitudes have no operational applications, avoiding them ensures a better efficiency of the "hard" protections.
In other words, the pitch protections restrain the potential dynamics of the maneuvers in order to improve the efficiency of angle of attack or overpeed protections.
If we consider the low speed flight domain for instance, a pitch attitude of +50° would lead to a very quick loss of speed (in kts per second) which might lead to a maximum angle of attack being overshot (during the maneuver) because the alpha-protection is not designed to react that hard or early (in terms of speed).