Are you sure that's what it is? From what I've heard time and time again it's confidence which is the most attractive quality in a personality, a clear sense of who they are and what they want. You can be confident without being violent.
A cave-man or a hunter (man) has only one meaning of powerful - physical. Today the meaning is changing, and Obama is powerful without having much body strength. Whether he is violent or not is something I will let you decide. But my point is that the anti-physical violence rhetoric one hears all day long is only a very recent phenomena and is directly related to what is considered more powerful today - war or politics.
NOTE: To people marking down my answers, what are your opinions about 'why women love cooking?' because statistically more women are found cooking than not, and 'why blacks like slavery?' because statistically more blacks were slaves than not? (HINT: Django Unchained anyone?)