Quite why this is so can be argued. It could be the patriarchy, the oppressions of capitalism, the manner in which we simply don’t have enough female politicians to sort things out properly. It could also be that this is just the way things work in a species that evolved as hunter gatherers.
An often monogamous and usually sexually dimorphic animal, one with an exceptionally long period of childhood helplessness, has a division of labour in the raising of offspring? Get away, it’s obviously ridiculous that hunters might provide a little more, gatherers nurture. Occam’s shaving kit does however insist that if we have two explanations which both explain all of observed reality then we should prefer the simpler.