Notice the difference in language:
- the man "had no interest in saving his kids", the woman "plead guilty to"
- the man was "evil", with no mention of his history of depression, but the woman was under stress from her partner's ex who supposedly got a witch doctor to put a spell on her
- the man killed his children by driving them into a dam, she drove her children into a lake, killing them (the order of details in both sentences is important, the latter inferring that she did not intend to kill them).
The man's history of mental illness and actually seeking professional help has not helped him in any way, but I'm sure the courts will take into account whatever hardships the woman has been through and reduce her sentence accordingly.
At the end of the day, both people made a conscious decision to end the lives of their own children, yet because of their respective genders (and race?) will be treated very differently.