Perhaps it does have an evolutionary purpose. Say you are a male who is constantly rejected by the female. If mate with the female, perhaps even against her w

Perhaps it does have an evolutionary purpose. Say you are a male who is constantly rejected by the female. If mate with the female, perhaps even against her will, then you produce offspring. Also, being rejected is a dominance issue. If rejected from more powerful members of the society produces aggression to the point of killing those more powerful then the aggressive individual rises to power and increases the odds of reproduction.