It is. What you're confusing is the difference between anaphylaxis and an allergic reaction.
NHS:
Anaphylaxis needs to be treated in hospital at soon as possible. Use an adrenaline injector if the person has one and call 999 for an ambulance.
But the 1 in every quarter of million figure being quoted is not that every one in the population who take the Pfizer vaccine will have an anaphylaxic shock every quarter of a million times the vaccine is given. The individuals in question will have been those usually at risk from a vaccine reaction.
And putting this in perspective: if a new vaccine is getting extreme reaction only 4x higher than most vaccines induce then that has to be seen as a success.
remember, we are in the teeth of a killer pandemic and most people will recognise that if they have the Pfizer vaccine then it will be a quarter of a million shot that they'll have a severe reaction, and that there are no reported incidences of anyone dying from the reaction.
Context is key here.