It is commonplace to use the most compelling cases as examples of social problems when trying to advocate for change. That's why, when we hear about Domestic Violence the examples provided are things like women being severely beaten or killed (a very, very small minority of cases,) even though when they gather the statistics that say things like "80% of women have been victims of Domestic Violence" their definition of DV includes things like economic, social, emotional, financial, psychological, etc "abuse."
Father's (aka men) are, apparently, incapable of feeling pain, or at least have done something to deserve it if they do, and do not make for sympathetic victims.
As such it's not surprising that, when trying to get tougher laws against parental kidnapping, they only talk about when fathers abduct children.
On the one hand I'm just glad to see that the issue is being taken more seriously and understand the way they need to position the issue in the social problems marketplace.
On the other-hand, I expect the same thing that's happening with the Hague Convention will happen with UK's kidnapping laws.
When a mother abducts the children they will say "no one ever anticipated that this law could be used against a mother," even though it was plain as day that the law could be used against either parent and anyone trying to tell you that no one could have foreseen such a thing at the time the law was written is, implicitly, also implying you are mildly retarded enough to believe such nonsense.