Is bullying the result of a natural evolutionary process?

Think back to our recent history. Before electrification, most families were between eight and 12 children. This time was agricultural and rural. Early radios were battery-powered and used sparingly.
Consider then family units and societies before the last 50 years. They were larger families, and geographically tightly knit social communities. The focal point of social cohesion usually centred around a church.
Consider another aspect drawn from biblical writings. It is described how the conquered nation marked the doorways of the firstborn. The firstborn marked to be killed. Knowing that a small amount of information from our history of a species, why? What did they know that because this to be standard practice?
Step back from this historical knowledge. Consider this from a biological species perspective. All organisms on the planet compete for resources. Within many mammals, the dominant male maintains a hierarchy over the herd. Dominance is maintained by physical superiority. The strongest of the species maintains a genetic lineage.
Why within our historical texts would we want to kill the firstborn of a conquered territory? Let's view this from a biological perspective. Consider that this is a one-time occurrence. Survival of the species must will attained by utilizing all the best attributes. At the genetic coding level, the fertilization process best equips the first offspring. The fertilization being able to detect ancestrial genetic material. During fertilization, an overlap of ancestral code, causes defects and reduced conscious abilities. The ruling families of Western Europe show this phenomena. Arranged marriages between cousins in the monarchy resulted in reduced cognitive abilities.
I would conclude that this is true of all organisms. Thus it may assume this to be a natural rule of nature.
Consider the previous century, many families averaged 8 to 12 children. There can only be one firstborn. The evolved social behaviour of the family and the community will be then the power of the majority. The firstborn would only be on average at best 8% or 10% of the general population. Consider that 85% to 95% of the general population would hold power over the firstborn. This is the observation in the school playground. The individual that gets picked on, or bullied, or subject to peer pressure is the firstborn. They are a minority by their birth circumstance. All other siblings develop social skills which the firstborn did not establish.
If we step back in time with this conclusion, ancient biblical texts, now assesed in a new way. Conquerors marked the doorways "of the firstborn". It was thus understood that the firstborn would be a future threat to assimilation.
The easiest to convert, dominate or assimilate would be not the firstborn. Why? All but the firstborn are easier conversions. As within beehives, Royal jelly causes the development of another Queen bee. Without the royal jelly, a worker bee will result. Those not the firstborn, predisposed to be in a social supportive role.
This brings to point another observation. that from the genetic pressure to continue the species at an individual level. The dominant majority within a social group is not the firstborn. Thus intimidation and bullying by the majority assure an available selection for breeding. The minority, being the firstborn, would condeed to the peer pressure and give in. Societies pass this off by stating "boys will be boys". Another one from our past, "he's seeding his wild oats".
Over many generations, what we see as toxic male behaviour, was the normal behaviour of the day. Guard dogs result from selective breeding for dominant behaviour. In previous centuries we have achieved dominant behaviour in our own species. This would be a general rule of social structure in large families. The first born may be of higher intellectual ability. Dominant behaviour would override intellectual ability. A population is in the hands of the dominant majority, the genetic material at hand is at a diminished value. Do the firstborn from these relationships result in the same "best possible" offspring? Yes, of course, they do. Because the firstborn will always use the best genetic material available. Yet, the best genetic material of the species in the majority of cases is not available. The highest achievement of genetic material used, would be from unrelated individuals. Firstborn of unrelated families would yield firstborn of the highest achievable genetic material. Consider that the Canada goose is monogamous, it has only one mate for life. Consider that our species pursues many relationships through its lifetime. This is nature's way of assuring the greatest genetic diversity. Only within faith communities, is there strict adherence to monogamy. This handed down within these communities for centuries. Our species is not by default monogamous, as with the example of the Canada goose. Western European descendents have thus achieved global dominance through the denial of promiscuity. Christianity with its virgin birth. Biology and genetics today would suggest that a virgin birth is impossible. Thus this story would relegate to a tale of promiscuity.
Look back at the Greek and Roman empires.  Observe that power was in the hands of those that claimed ethnic purity. In all aspects of our modern age of agriculture through the use of genetics, we breed for specific traits. Passive temperament would be the selective breeding choice for the pet industry. I would suggest that the Greeks and the Romans were breeding for a stronger military force. A ranking Roman officer brought home the woman of his choosing from conquests abroad. Let's throw in another curveball. The conquest of Knights was one of honourable duty. They were according to the historical record, "in search of the Holy Grail". Understanding of the interaction of genetics in our current time, I would suggest this. That "the Holy Grail", was female genetic material. This was the new genetic material brought back to the homeland, that would produce firstborn which would be better genetically equipped than those of the general population. It would be perhaps these firstborn of the high-ranking officers, that would follow in their father's footsteps of a military career, or be intellectually capable of attaining a high position within the religious component.
-------------------------------------------