There are really two separate issues here. One is the phenomenon of the "family annihilator" and the other is how the media tends to report incidents where a man kills his partner and/or children, often before killing (or attempting to) himself. Both are certainly feminist issues.
This 2008 report on murder-suicides in the US, found that only about 5% of murder victims of murder-suicides are male and 74% were murdered by an intimate partner (who then committed suicide.)
This File on 4 programme from March of this year discusses similar features of cases where men kill their families and then themselves.
Family annihilators don't always have a history of mental illness. Many have been abusive towards their partners or at least have had quite "controlling" tendencies related to their families. Sometimes, they have careers where they are required to compete and/or are in positions of power and status. Conversely, they are in jobs of a lower status, but play out their need for power and control in the domestic sphere.
It seems they are most likely to kill if they feel their control over their partner and family is at risk. For example, they might have lost their job or been convicted of a crime or something else that means they feel they can no longer be the "provider." Most commonly, however, it happens when the relationship is breaking down or has ended, which signals to them that they are losing control of their family. Some will kill the children as the ultimate punishment for an ex partner, but it has also been suggested that those who kill their children and not their ex partner may do so simply because it is easier to get the opportunity to do so.
Once their family are dead, the man then literally has no purpose in life, if his obsession in life was to control them, so that's when he commits or attempts suicide.
Basically, the phenomenon seems to stem from a belief in male entitlement taken to an extreme. Although there are often signs that something could happen (e.g. man with history of abuse and/or control, experiences sudden change in his position and/or end of relationship, etc.) which agencies could pick up on, they are rarely noticed until after the incident. Even where the woman, a relative or friend reports concerns to the police, these concerns are rarely acted upon. Lives could be saved if there was greater awareness of the problem and a commitment to intervention to protect women and children at risk.
The media tend to be very, very coy in describing incidents where women are killed by their partners. Quite frequently it will be something very brief like, "A man and a woman in their mid 30's were found dead in Acacia Avenue this morning. The incident is being regarded as unexplained but no one else is being sought in connection with the killings." If you aren't paying attention and don't read between the lines, you won't "get" that it was probably a man who killed his partner then himself. While tabloids will splash lurid headlines about murder and violence, particularly where the perpetrators fit the model of "villain" quite neatly, it's as though hacks are afraid to frighten the horses if they more than whisper that a man has killed his partner in cold blood.
But, sometimes the stories break big, particularly where there are children killed. Then something of a "formula" is followed for reporting. Lots of photos of cute children, children smiling with their dad and happy family shots. Statements from friends, neighbours, teachers, etc. about how happy/pretty/clever the children were. Statements from co-workers, neighbours, friends about what a loving/caring/hardworking/committed father the killer was, with much hand wringing about what would "drive" him to do this. Comments about him being under pressure/depressed/stressed/worried generally follow.
Then there are almost always insinuations about the dead woman. She left him/was threatening to leave/was restricting access to the children/was having an affair/he thought she was having an affair/he was worried she would have an affair/she was demanding/she spent too much money, etc. Dead women tell no tales but there are always plenty of people willing to tell tales about them, whether there is any truth or not.
The goal of such reports really seems to tug the heartstrings over the loss of "innocent" children's lives, attempts to excuse or justify the man's actions and efforts to demonise the dead woman. If they succeed in this goal, then we can swiftly forget that women are far more at risk of being killed by a partner than a stranger. This stops us worrying about the inequity in many male / female relationships and the serious risks many women face from their partners.
It's late and I don't have time to look up more links, but most of the literature suggests that women who kill their children are more likely to have a previously diagnosed mental illness than men who kill their children. Women very, very rarely kill their partners then kill or attempt to kill themselves.