The dirty secret is that they love death, so they actually think that all these deaths were a good deed. To eugenicists, all these deaths were not just an unfortunate by-product of over-zealous adherents (of course, they try to pin them on something else). Over-population is one of their creeds.
I am not saying every evolution promoter thinks that all these deaths are a good thing. But to a eugenics and over-population believer, thinning the herd is a good thing, at least in theory, and if it isn’t their family or themslves who are being thinned (at least involuntarily).
Here, this is by Darwin Medalist Karl Pearson. He was addressing an audience of doctors and surgeons:
Let me, even at the risk of talking about the familiar, sketch for you the broad outlines of Darwin's theory of evolutionary progress. The individual better fitted to its environment lived longer than its fellows, had more offspring, and these, inheriting its better fitness, raised the type of the race. The environment against which the individual had to struggle here was not only formed by the other members of its species, not only by its physical surroundings, but by the germs of disease of all types. According to Darwin -- and some of us still believe him to be right -- the ascent of man, physical and mental, was brought about by this survival of the fitter. Now, if you are going lo take Darwinism as your theory of life and apply it to human problems, you must not only believe it to be true, but you must set to, and demonstrate that it actually applies.It seems that Darwinism is anti-medical-progress.Darwin's theory means this, that if individuals are reared under a constant environment, and a larger percentage of them are killed off in the first year of life, then a smaller percentage of those remaining will die in the later years of life, because more of the weaklings have been killed off... Now if there be -- and I, for one, think that two independent lines of inquiry demonstrate that there is -- a fairly stringent selection of the weaker individuals by the mortality of infancy and childhood, what will happen, if by increased medical skill and by increased state support and private charity, we enable the weaklings to survive and to propagate their kind? Why, undoubtedly we shall have a weaker race... Surely here is an antinomy -- a fundamental opposition between medical progress and the science of national eugenics, of race efficiency. Gentlemen, I venture to think it is an antinomy, and will remain one until the nation at large recognises as a fundamental doctrine the principle that everyone, being born, has the right to live, but the right to live does not in itself convey the right to everyone to reproduce their kind... Our social instincts, our common humanity enforce upon us the conception that each person born has the right to live, yet this right essentially connotes a suspension of the full intensity of natural selection. Darwinism and medical progress are opposed forces, and we shall gain nothing by screening that fact, or, in opposition to ample evidence, asserting that Darwinism has no application to civilised man... I say that only a very thorough eugenic policy can possibly save our race from the evils which must flow from the antagonism between natural selection and medical progress.
--Karl Pearson