These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fridge Logic: If the world would end once the last evil is eradicated, then it appears that the last evil could not possibly be eradicated, because the world ending would be the last evil. Of course, In-Universe, nobody may realize that.