Why can't an atheist have consistent Logic?

Your stupidity is quite humorous. The reason it is immoral to eat a child, a *born child, is because a) a *born child has both the ability to be self aware and the ability to think, b) assuming the child wants to live, killing the child would conflict with his or her freedom to live, c) the purpose of life is to enjoy oneself, and killing another human is ending a person's ability to enjoy life. As to animals eating their young, that is quite rare (some species of shark do it), however the same cerebrum advancement (the cerebrum controls thought and self awareness) is not present among those animals, thus the logic behind the morals are non applicable.