In the context of a harsh, dangerous environment, the dominant male is valued because he can get what he wants, and provide resources to those who will submit to and follow him. He doesn't need to employ skills beyond strength and intimidation. But outside of pure barbarian society (i.e., most of human history), it's the prestigious man who rules. He's primed to have the most access in the widest variety of circumstances.
Our political system is highly competitive, frequently dangerous (less actual assassination, but still tons of character assassination) and tends to reward those bombastic types who thump their fists on desks and shout to get what they want. How many people still love Rob Ford's approach without making the direct link between his "leadership style" and his personal problems?
Conversely, these are the types of selfish bosses who think nothing of throwing their colleagues, public servants and even direct employees under the bus without batting an eyelash. They are not prone to step up and offer support to a besieged group or individual unless they see direct benefit from doing so or loss from staying silent.
This goes for both genders - it's the personality that dominates. That's how the system functions.
Of course, our political system doesn't work. Not only are we landing with ideological policy that is poorly constructed and not as reflective of social need as it should be, but we have a populace that is tuning out entirely, so fed up with the "blood sport" and entitlement we all associate with politics.
Of course, things are changing; Tim Hudak isn't the only aggressive, attack-centric bombast who's found themselves marginalized in the recent past. We also have a crop of leaders emerging who do the sociology thing - and aren't all men.
Just something to think about.