Of course, Arimidex is often used by steroid users to decrease over-aromatization from driving their testosterone into supraphysiological zones, . way above normal, which in turn leads to elevated estradiol. They aslo use it post-cycle period when they are desperately trying to get their testosterone jumpstarted - sometimes unsucccessfully I might add. As strange and annoying as this is, steroid users and fertility doctors were some of the early pioneers of Armidex usage.
The second theory is similar and is known as "evolutionary neuroandrogenic (ENA) theory of male aggression".   Testosterone and other androgens have evolved to masculinize a brain in order to be competitive even to the point of risking harm to the person and others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens enhance their resource acquiring abilities in order to survive, attract and copulate with mates as much as possible.  The masculinization of the brain is not just mediated by testosterone levels at the adult stage, but also testosterone exposure in the womb as a fetus. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game.  Studies have also found higher pre-natal testosterone or lower digit ratio to be correlated with higher aggression in males.