Today's tragedy breaks my heart too, but talk is of the weapon rather than the reality
A mentally ill young man STOLE the weapons
Approximately 45 young people are killed every day by automobiles. EVERY DAY, DAY AFTER DAY, 365 DAYS A YEAR. About 100 people killed a day total. A large portion by drunk drivers (almost 40% IIRC).
Many teenagers don't need cars, there are buses, many older folks should not be driving. Many habitual DUIs should face life in prison but the weapon they use and the intent somehow justifies it in the minds of many.
From what I can read about the incident, he was not mentally ill, he was likely one of the sanest and brightest people in that little town. But he was different, and people of merely average intelligence can be terribly cruel to anyone who doesn't fit their mediocre little mold. He needed only one more step on the road to maturity -- to realize that the opinions of people who, compared to him, are idiots simply don't matter.
Not to condone Christianity, but a famous line from the New Testament is apt: He needed to learn to forgive them, for they know not what they do.