> Case fatality rates were noted in three studies at 0.000002%, 0.00009%, and 0.0001%.
Fatal allergic reactions are so rare as to be completely irrelevant as a cause of death. Most of them are drug induced and most of those occur in hospitals when someone has an allergic reaction to an intravenous drug, not something they eat [2]. They're unlikely to be a significant driver of any evolutionary adaptation.