But that is true regardless of whether a male is fit enough to survive a cannibalistic female, which means that pacifist females do not have an advantage in natural selection:
As long as there are enough males in circulation that can succeed in fertilizing before being eaten, then there's no pressure on females to drop the cannibalistic strategy. Any male that cannot win the cannibalism game can only fertilize pacifist females, but a male that can win the cannibalism game has genes that can be passed on to both cannibalistic and pacifist females. So the genes of cannibalistic females have broader reach within a species that has already gotten to majority-cannibalistic because her male offspring can fertilize both types of female rather than just one type.
Again, to GP's point, just because non-cannibalism would be more beneficial to the species as a whole doesn't mean that evolutionary pressure on individual genetic lines will select away from it. The individual line is often better off being selfish and selecting the strategy that gives them the broadest possible range of propagation (hence Richard Dawkins' title, The Selfish Gene), which in this case is cannibalism.
