evolutionary reasons for abusive behaviours

the reason that abusive behaviours are wetwired into the brains of so many humans is because during the stone age it was a highly succesful strategy for parasitic individuals to abuse a high value individual 

when parasitic individuals abused a high value individual 

then there was no punishment because there was no apparent crime 

so parasitic individuals were not beaten to death like a thief 

and when parasitic individuals abused a high value individual 

then that high value individual became distressed and made mistakes 

and mistakes led to injuries or sickness 

and during the stone age there was no efficient healthcare system 

so a injured or sick individual usually died earlier 

basically abusive behaviour evolved as instinctive behaviour wetwired into the brains of many humans so that they would be able to decrease survivability of others to increase their own survivability 

humans are supposed to have a neocortex on the surface of their brain that is a few millimeters thick where free thought is supposed to happen 

but if a human is pushed by need for food, sex and shelter 

then instinctive behaviours takes over 

in the same way a person hurries to toilet when need arises to defecate