I've worked in the family justice system for 30 years, and still do. I've represented parents and the children through their guardians. There is no gender bias, that's a fallacy.
Both parents see their kids unless there is a cogent reason otherwise. That's the law, it's how it happens in practice and it's wrong to suggest that courts shut kids off from seeing a parent for no good reason. I've dealt with hundreds of cases where contact cannot take place safely, or to be safe it must be supervised. There not cases where fathers have been treated unfairly, rather cases where the court has made orders in the best interests of the children. Sure, there'll be cases where the court make decisions that a parent feels is wrong, but to be frank one never knows where the truth lies and the court must do it's best with the evidence available.
There are cases where parental alienation happens, and it's very sad when it does. However, that's a different issue and not the justice systems' fault. rather, that is a parent who is unable to put the child's needs above his/her own feelings. That said, I've dealt with loads of cases where the courts have fought hard to reinstate and maintain contact against that background with the use of psychologists, guardians for the children, and policing/enforcing the orders it makes. I've also dealt with a number of cases where residence has been flipped as that's the only way that the child can have an effective relationship with both parents. The key in those cases is to act quickly - delay allows the rot to set in and that can be tragic for the kids and the impacted parent.
You make a good point re representation. The lack of availability of legal aid in these cases will inevitably mean some rough justice, that's indisputable. McKenzie friends can help with assistance, but many of them can do more harm than good and some proper legal advice, even just a short chat with a specialist, is vital.
Genuinely, fair play for supporting people in these cases.