Why didn't Laurel Harper do more to curb her son's violent tendencies? Shouldn't she have seen this coming?  Writings from "Tweety Bird" (the Yahoo account name linked to Harper) appear to indicate that she did this even as she told others she worried about her son's violent tendencies. Tweety offers that her son was a "headbanger," and was a child who had been diagnosed with Asperger's syndrome -- which she also had, according to a Tweety post. (Studies have shown there is no direct link between Asperger's and violence.)  And yet, according to her neighbors, Harper brought her son to shooting ranges. Police would eventually recover 14 firearms from the two -- six from the shooting, and the rest from the apartment they shared.  Indeed, it's hard not to point the finger at Harper, a mother who most assuredly knew her son was not entirely stable. According to a former colleague, she had hospitalized him when he refused to take his medication. And yet she apparently allowed him to have access to an arsenal. Perhaps she thought the guns might provide a necessary distraction from a troubled existence. By all appearances, Tweety Bird thought it was his right as an American.  Still, while it is undeniably irresponsible for any parent to foster in a troubled child an interest in weapons, to blame Harper for what happened at the hands of her grown son is to ignore the many other factors that may have contributed to the tragedy.  Children develop interests and often look to those adults who can help nurture them. There's a good chance that, had his mother not been interested or available, Harper-Mercer might have sought out another person to talk with about guns and the horrendous result might have been the same.  But while she was certainly the major adult influence on his life, even the most sheltered person, by the time he has reached 26, has been also influenced by a wide range of experiences and factors.  To blame Harper is to absolve, for example, the people who may have bullied or rejected him over the years. It's also to absolve the community that, if Harper does have Asperger's, may not have provided her the support she needed to care for a child.  And, it should be noted, she largely raised her son alone. Harper-Mercer's father, Ian Mercer, was out of the home for much of his youth. Few fingers point in his direction, of course, because we live in a culture where blame falls on the mother, for anything and everything.  Although many studies (including my own) suggest that sons of single mothers do not necessarily fare worse than those raised by two parents, single mothers may tend to be more protective than mothers who have the help of a second parent or partner. According to news reports, Harper was extremely attached to her son, her life with him quite insulated. Had his violence not, finally and horribly, erupted, one might have viewed her attentions to him as simply an overweening expression of a mother's love.  Judging by Tweety Bird's confident dispensing of advice online (she is a licensed practical nurse), it seems likely that, if she needed help, she may not have recognized it.  Harper may have made bad decisions, but they may have been the only decisions she knew. It's unlikely she intended to harm or turn her son into a killer. But she appears to have struggled -- with acceptance, with a troubled son, with the absence of the boy's father, who was not around to help provide influence, or support.  And let's not forget to consider in culpability the increasingly violent imagery kids see every day and the too-loose gun laws that allow this sort of tragedy to happen again and again. Though all the guns in the Harper-Mercer household were purchased legally, there's certainly reason to question whether a system in which guns were rationally regulated would determine that a single mother and her 26-year-old son needed so many weapons.  Still, to try to pin the tragedy of Umpqua Community College -- the tragedy of Christopher Harper-Mercer -- on any one person or event is to avoid the truth: That what happened to him -- what happened because of him -- is the result of an entire nation's worth of inaction.  And such events will continue to occur if the resources for people such as Laurel Harper, and the laws for who can own guns (and how many), do not change. There's a bigger problem in this country than one irresponsible mother, and I think most of us know that.  Join us on Facebook.com/CNNOpinion.Read CNNOpinion's Flipboard magazine.
It's common -- and comfortable -- for society to blame mothers, not fathers, for a child's development. But many other factors are at play.