Imagine a population where two alleles exist for one gene: allele A at a frequency of 90%, and allele B at a frequency of 10%.
Allele B causes a disease which reduces individuals' genetic fitness by half. This disease can be treated by some substance, e.g., spinach, in which case normal fitness levels are attained.
If B carriers are left untreated, then at the next generation the frequency will shift to 94.7% for A (=90/95) and 5.3% for B (=5/95), and in subsequent generations the frequency of B will continue to decrease until A is fixed in the population.
Suppose that some regime (HARSH) uses a policy, in which everyone is given the same deal (=no spinach). Under this regime, the allele B will disappear as quickly as possible. We can say that HARSH practices a type of egalitarianism, as it treats everyone the same.
A second regime (NAIVE) gives spinach to everyone. Assuming that spinach doesn't hurt normal (A carrying) individuals, then this will result in the frequencies of A and B remaining the same. This is also egalitarian, but it results in the opposite effect, the maintenance of the genetic status quo rather than the rapid disappearance of B as in the HARSH regime.
Finally, a third regime (SMART) gives spinach only to B carriers. Again, B will be maintained at a frequency of 10%, but in this case the regime gave spinach to only 10% of the population, a much smaller cost than the NAIVE one. The policy of SMART is non-egalitarian, as B carriers got a special bonus.
The above examples were hypothetical, but they correspond to real concrete policies carried out in the real world.
As an example of a HARSH strategy, eugenicists were traditionally worried about how modern society's inventions were allowing for the survival of the "unfit", while in ages past natural selection weeded them out.
On the other hand an example of a NAIVE strategy is the adoption in many countries of universal health care plans. These benefit mainly the poor members of society, since rich individuals are generally in better health and can afford to pay for health care on their own.
Finally, a SMART strategy is applied often in medicine, where drugs are administered only if they are likely to improve a person's health. But, this is not always so, as medical organizations often make generalized diet and lifestyle recommendations addressed to all, even though they do not benefit all, and indeed might even harm some.
All three strategies have the potential of misuse, and are thusoften met with resistance. For example, the HARSH strategy is inhumane, as it strikes us as fundamentally wrong to see a problem, know that there is a solution, and yet fail to apply it in the interest of "equality". Similarly, the NAIVE strategy is seen as wasteful, as resources are invested equally to all, even to those who do not need them. Finally, the SMART strategy has an element of preferential treatment which bothers our sense of justice. We might not care so much if the "spinach" corresponds to e.g., aspirin, but if it is expensive drugs or social programs, then we might oppose them.
Human history is marked by the continuous invention of new "spinach", such as printed books, wheelchairs, eyeglasses, hearing aids, etc. that allow us to function despite our deficiencies. Societies try to balance concerns about equality, efficiency and justice while administering these means to its members.
If there is an ideal state at the end of this historical process, we might imagine that this would entail mankind's mastery of essentially limitless resources, coupled with a deep understanding of human nature. This will allow it to apply the SMART strategy to those who need it, while at the same time the rest will not mind, as their own resources will not be affected by this preferential treatment.