That makes absolutely no sense, as the people who are going to be coming into this situation are the most experienced fighters. You'd think a level 20 fighter would know much better how to not get hurt by his own weapon than a level 1. Yet, the 20th level is going to come into the situation where he *can* be hurt by his own weapon (even if he 'confirms' all the time) much more often than the 'newbie' fighter.
This alone shows that "Critical Fumbles are balanced by Critical Hits" is sophistic. The better and more practiced someone gets with a weapon, the less chance she has of doing something like hurting herself or dropping it or whatever. That's not the case with critical fumbles, as the situation comes up more often with the more attacks you have.