> Moreover, you will see same numbers as for salary difference.

Is your argument that since there seem to be a correlation between mortality rate for boys and higher salary for men, that there is some kind of causation that make it good? You really have to expand on that if you want to make it comprehensible.

> Natural selection did not stop that, so it's beneficial for society somehow.

Here you reveal that you don't understand natural selection. Natural selection doesn't select for what is beneficial for society at all. Often what is good for the gene is bad for society, and the other way around.

Natural selection works on time scale much longer than the industrial revolution, and most factors are probably older than agriculture. It would be rather stupid to let what was useful behaviour 100k years ago control our lives today. We live in very different environments, in very different societies, and faces very different dangers.