It's very broad, just off the top of my head:
It's part of the whole make up of our society, which is based on exploitation and inequality, that's what capitalism is. If there wasn't a strong ideology that some of us deserve to be exploited then it wouldn't function in that way. The whole thing is based on exceptions to equality, some people are worth less, less human than others, women, working-class people, black and brown people etc. Some are the exploiters and the rest are exploited. Critiques of the family, when they were fashionable, used to involve an idea that men took out the humiliations of the workplace (in which we have little power) on women and children at home. I don't hear that kind of critique anymore.
Psychoanalytically, the idea is that people, unconsciously, project their vulnerability into others, where it is despised. This begins very early, and it will take the form of the culture children are a part of. Tough boys become tough by projecting their 'weakness' elsewhere, into girls, into gap people, it's put out there. This can get stuck and concrete, and these other people, people who are seen as part of a group who share characteristics, become hated. Add some paranoia - it's all their fault - and it's very toxic.
Many boys are referred into CAMHS for aggression and violence. There might be family difficulties, exposure to dv, sometimes neurodevelopmental difficulties. Girls too, but not so often, I don't think it's taken as seriously. Boys violence scares people, they don't know how to manage it- 'what happens when he's bigger than me and he's like his dad?'
And then, there are some children who are severely neglected, subject to or exposed to violence, the use of drugs and violence, terribly abused or tortured even who go into care and their hatred might be evident from quite young, there are some children who enjoy hurting and killing animals. Its hatred that should be the red flag, not only hatred of women, that's the shape that hatred takes, and that shape might be more obvious later, but the underlying warning that a child needs help is hatred, and taking pleasure in hatred, and a belief that if they are not to be the prey, the victim, then they must be the predator. And this needs to be seen, alongside their vulnerability, and not turned away from because we don't like to think such things about children and they need the right therapy, and well-supported carers, which has a chance of helping.
I think the use of drugs and porn really amplifies any underlying hatred. It gives that hatred a form and offers excitement. This is a massive problem.