It's primal instinct. We're hardwired to respond to female distress because each female is vital to the reproduction of the tribe. We are hardwired to ignore male distress because any man can spread seed to many and have lots of offspring, so helping them is a waste of resources. It's all about the collective, the tribe. Aka communism. Our instincts are not good, none are, but humans are especially bad, being excessively aggressive and socialistic herd creatures. But we don't resist them because in our pride we've convinced ourselves that we are not animals and don't act on instinct, when really we do.