Primitive?

Two sides of an argument in which the former views the latter as primitive while the latter views the former as immoral and inhumane. Primitive, according to Dictionary.com, in an Anthropological context is defined as, "of or pertaining to a preliterate or tribal people having cultural or physical similarities with their early ancestors: no longer in technical use." Something that was useful in a bygone age but is now technically irrelevant. Something that was good for then and those people, but not for us and the people of today. The latter are considered old-fashioned, obsolete, and against progress. But what is progress to the former argument? Natural selection? Only the strongest should survive? Only the brightest, fastest, smartest, and most adaptable should survive. In nature, only those ones are the ones who survive, so naturally that should be true of the human race as well. In nature, the sick, the handicapped, the runts, and the weak are the ones who are preyed upon and killed. The weak ones are exploited to reach the greatness of the stronger ones. Instinct for survival is what drives survival of the fittest, an animal is driven by the instinct to survive at all costs above all others. Should humans too hold themselves to the standards of nature? The former would argue so. The latter says that we should love our neighbor, that we should take care of the sick and the hurting and the handicapped. They do this because they believe that every person has value and every person is created with purpose by God. Therefore if everyone was created with purpose, every person (despite any defects or handicaps) has value and should be given the right to enjoy a full life. Which view is actually primitive? Is the belief in God a crutch for people who don't want to believe in science? Is He a crutch for ignorant people to never observe the world objectively or scientifically? Was He just good to satisfy a superstitious people of a bygone age in who they had no science to explain the phenomenons they were experiencing? Is God obsolete? The former would say so, they would say that nothing in this earth cannot be explained by observation of natural means, so why would we need God. Mankind can be perfectly functional on their own without on outside force to tell them what to do. Which worldview is primitive? A worldview that believes that not everything can be explained in nature, and that ethics is based on God and His value of man's life over nature, and that man should be loved above all else on earth, or a worldview based on only the observable ethics of nature in which human and animal have the same value as cohabitators of this planet in which we define life by the survival and advancement of the species by killing the weak to make the species stronger? Which worldview is really more primitive?