Why not?
If every person who died of lung cancer had smoked AND used multivitamins, causation would be on the table.
Should be on the table here too. Along with weird liberal values, antidepressants, and interest in the Occult. These slaughters by liberal young people have NOTHING to do with guns... and everything to do with rage, envy and hatred, and alienation from fathers.
As I’ve seen, there is a VERY high correlation to both liberalism and to a missing parent. It’s not 100%, but there’s clearly something there. That is not complete though, as there is also a persistent thread of anti-religion in many of the shooters. This is not to say that there is not a strong mental health issue, and several other issues....but missing fathers have been shown to generally greatly increase a child’s tendency towards being unable to delay gratification, and moreso, towards acts that require incarceration.
...and the Zombies 'ill getcha eff you don't watch out!