As it has already been pointed out humans do engage in rape, murder and poligamy just as much as other organisms do and in some societies, present and past, people who engaged in these activities have been venerated.
I'm also somewhat confused by your comment that scientists see these things as positive processes. Scientists take an objective stance and see these things as neither positive or negative, they just are. There is no double standard.
Humans are not unique in the way you want them to be. Like all organisms they have a set of behaviours both inate and learned whose expression is determined by their environment. You only have to watch other social species interacting to notice that we aren't all that different.
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