Vegetarians are not preventing plants from doing reproduction.they allow them to grow , flower, fruit.And after preserving their seeds only we normally consume.They do not uproot a plant fully (in most cases) and they use only a par of the plant body.consuming eggs (unfertilized) is not cruel but killing a bird which may lay egg in future is cruel.And carnivores dont have a choice they have to kill for their survival but human have some alternatives.so he can avoid killing entire animal instead he can consume egg, milk etc.,so that they can also enjoy their life on earth for some time as we do normally.
