Which society is more likely to survive?
The society that believes the survival of the fittest individuals is most important? Thus they destroy others within their group that don’t measure-up to some arbitrary ideal. Don’t bother to help others in their group since they should be able to fend for themselves. Believe immunizations perpetuate a streak of weak genes through the population.
Or the society that believes the survival of the group is most important? Believe that all individuals can contribute to the group in some way. Believes the group is more likely to survive because of its variation of traits and genes. Knows that those who die due to disease or accident may have been able to save them in the future.
Society #2 though the differences between the two aren’t quite the way you label them in the first sentence. Both societies actually believe in survival of the fittest or at least evolutionary science (society 2 by understanding variations in DNA clearly has a grasp of evolution), the real difference is society 1 is eugenic and wants to drive evolution, and society 2 is Darwinian and is just allowing a natural process to do what it does.