I'm afraid that I unaware of evidence that mass murders are a Christian problem whatsoever. Nor does it seem to be a political "radicalization" issue, as would be similar to what the UK saw during the Irish troubles, to take one of several possible examples. But I think that people might better describe it as serious mental health epidemic of as yet poorly understood origin. (Pick your poison: drugs, social media, social climate, etc.)

Some people have put forward decent ideas on how we could restrict firearms from such individuals. (I personally think that everyone purchasing a firearm should have to find a longtime acquaintance to swear under penalty of perjury that this person is fit to own a firearm. Maybe others have better ideas.) Regardless, I hope that that situation can be improved somehow.