I think this a case of the 'tail wagging the dog'. The author decided she wanted to be vegan for (possibly) superficial reasons. She then found she couldn't be vegan for health reasons, but rather than take a step back and hold on to some of the principles she claimed to have (and become an ovo-lacto vegetarian; and see if that worked) .. cognitive dissonance came into play and she shifted her entire world-view aroun…
Some people might _need_ to eat animal derived products to function - but that should still be able to be compatible with a desire to ascribe to vegan ideals. When a person chooses involve politics in dietary choice, pragmatism should still be able to operate. Fundamentalism at any level is a bit wrong.
I don't see why the alternative - of becoming a fully fledged carnivore - was taken when there was an intermediate step.