Fundamentalist Darwinism requires that we treat everyone as our competitor, that brother's hand shall be raised against brother in bloody warfare for all eternity. This is an obvious requirement of the 'Law of Survival of the Fittest', because if we take pity on a weaker or less ruthless individual it will supposedly do harm to our species.
The Law of Survival of The Just-Barely-Fit, however, makes altruism a virtue.
That species which is cooperative, which has compassion for the weak and disabled and helps them to survive, will attain the greatest degree of variation of characteristics possible in a particular environment and will thus have a better chance of survival as a species. Species survival does not call for intra-species competition, it calls for the maximum degree of intra-species cooperation that can be managed.
In some species that isn't a primary mode of operation, but cooperation is inherent in human behavior. Our evolutionary advantage over the other primates is that we communicate with one another using abstract mouth-noises as well as the body-language that is the common primate inheritance. This allows us to cooperate at a much more subtle level than the other primates can, in that subtle and complex behavior we call culture.
Not competition but cooperation is the behavior blessed by evolution, for the human species if not for all more complex animals.
Furthermore, to the extent that the base of cooperative activity that generates culture is tolerant of variation it is more likely to survive. The cultures that have survived are those that can cope with change, can live with the insecurity that comes along with creativity. Creativity produces variation, and variation increases survivability. All else equal, that culture which provides the most opportunity for creativity is the culture which is most likely to be the base for the future.
Realistic science doesn't require that we hate our neighbors. In fact it says that acting less than altruistically is treason to the species; it is acting against the evolutionary flow. Thus Darwinism was not scientific, it was just an ideological excuse for acting badly. Ruthlessness toward members of the same species is not only unethical and unaesthetic, it is perverse, against nature.
Why would such an unscientific theory have passed as science?
The Darwinists were primarily well-to-do melanin-deficient people; and the notion of 'survival of the fittest' made it possible for them to justify their exploitation of people from less industrialized cultures and with normal or rich melanin concentration. Those dark skinned, unsophisticated people were obviously "unfit" because they were poor and unindustrialized and easily dominated by modern politics and armed forces.
Darwinism was simply racist political propaganda in the guise of pseudoscience.
We can now replace it with real science.