Ladies of BF - it's testosterone. Males have far excess of what you females would ever achieve without pharmacologic stimulation.

It makes men do stupid things and engage in stupid activities. Like lion hunting. Or bike racing. Take your pic. I do my fair share of them myself, and I'm usually considered one of the most gentlemanly of the crowd.

A lot of the juvenile and superficial male behavior you see commonly has do with this male-female difference. It doesn't excuse it or make it correct, and we males have to take responsibility for the fallout, but that's reality.