I've never understood the psychological reasons behind pointless social commentary during moments of tragedy such as this.
My social media streams were full of blather: "I feel bad for the parents and kids", "I hate school shooters", "I hate kid killers!!...ad nauseum. No kidding! There is a support group for people like you, it's called Everybody.
Why comment at all? Is it some coping mechanism? Do they feel as if they will be judged because they didn't publicly admonish the shooter?