A disoriented pilot, who had never been inverted before, who is inverted with local "positive" G, has very little time to react before he will be nose down, accelerating toward the ground at or above Vne. The risk of unloading - even a bit of negative G - is MUCH less than the risk of a terminal dive. Also, rolling with positive G will stress one wing more than the other, increasing the probability of damage.
UNLOAD, roll, pull. Throttles to a mid position (above idle, below cruise) simultaneously.
Note that the SAME technique works for nose high. The roll is to knife-edge (or slightly beyond 90 deg) in this case, allowing the nose to fall toward the horizon. Also, you do less damage to your situation if you roll the wrong way initially.