You are aware, aren't you, that Rogers stabbed to death three of his victims, and so even if he did not have access to a gun, he would have been guilty of a heinous crime.
This is not a story about misogyny or guns, it is a story about a mentally ill person going on a rampage.
Ultimately, any chance of preventing this incident would have depended upon the recognition of his being dangerously disturbed, and the willingness and ability to remove him from society (hopefully to obtain the treatment he needed).
If our society is capable of recognizing the mentally ill who present a clear and present danger to innocent citizens, focusing that information on denying them access to guns is ridiculous. Obviously they shouldn't have access to guns, but it's their mental illness not their access to guns that leads to murder. That Rogers killed three people with a knife is proof of the fact that simply denying the mentally ill access to guns cannot prevent these rampages.
In addition, it is not a simple task to deny the mentally ill access to guns. Even means to prevent them from legally accessing guns is imperfect and can punish those who have experienced mental illness but have received successful treatment. The only fool-proof method is to eliminate guns from the face of the earth, and that, quite obviously, is never going to happen. I would argue that outlawing personal ownership of guns is also never going to happen (or at least not in our lifetimes) and that doing so would not be fool-proof.
The best and only remotely reliable chance to prevent these killing sprees is to improve the recognition and treatment of mental illness, however this carries with it a number of difficult questions we as a society must answer.
Are we willing to allow for the forcible, if necessary, examination, detainment and treatment of those who evidence signs of mental illness?
Do we trust the authorities to properly exercise this power, and to what extent are we willing to tolerate errors and abuse (as both would certainly occur)?
Are we willing to allow the government a much greater access to our personal information, including, obviously, our medical records?
Are we willing to provide immunity to those individuals and healthcare workers who alert the government to a potentially violent madman?
What do we do with the individuals who have never committed a crime, but whose mental illness proves untreatable? Are we willing to tolerate preventative imprisonment (even if the "prison" is a mental health institution)?
Certainly we can get better at denying access to guns to the mentally ill, identifying potential killers, and actually treating mental illness, but only around the edges. It's been said numerous times before that these crimes invoke in people considerable horror and fear, and a demand that they be prevented in the future.
Unfortunately meeting this demand is considerably more difficult than anyone pushing a single issue understands, and, frankly, I don't think those who appear after every one of these tragedies occur, declaring that they know the reason for them (gun ownership, bullying, Jed Aptow nerd movies et al) and demanding that these causes be addressed, are really all that concerned about preventing future crimes.
Any and all means of preventing tragedies like this one or Sandy Hook, or Columbine, involve the restriction of individual rights. For some, such restrictions seem entirely reasonable, while for others they are intolerable. It seems to me that before any of our existing rights are restricted or eliminated, we should have a much better idea of whether or not doing so has any real chance of actually being effective, and not a result of emotionally charged reflex or separate ideological agendas.