Because dad is a dick and doesn't believe in sharing equal responsibility for parenting. Not all men are like this, but many have been conditioned to believe that men work and women raise the kids. Even if it has eroded there is still traces of that mentality. 

This is based partially on biology. Women are natural caretakers. Being able to raise kids and take care of the household does come more naturally to them. Honestly how it should be is that parents earn an income, raise, and teach at home. They share on equal responsibility for child care. 

Not letting indoctrination camps pretending to be schools raise your kids and teach them that its OK to cut off your dick and that makes you a girl. While they grow up unable to take care of themselves in the real world, because they weren't taught how to be real fully functional adults.