I certainly agree, but, alas, people will do it anyway. They go around judging everything and everybody without the slightest effort to understand the other's point of view, or the impact of their words. I don't think this is something new: there was someone who talked about it a long time ago, what was it....Judge not lest thee be judged. And something about casting stones. IIRC, the same person, in a pretty unpleasant situation said 'Forgive them, for they know not what they do'.
I feel great empathy for the family and friends of the teens, but IMO their pain isn't really because of public opinion (it's always easier to blame strangers). They've been profoundly betrayed by AS and KM, who probably didn't understand and didn't care about the impact of what they were doing on the people who loved them. Young people are very stupid and careless that way.
The family and friends are going to have to suffer through their grief and loss, there's no way around it. I hope they can do it without blaming themselves, blaming the teens, blaming each other, blaming police, blaming the victims, or blaming the public (blaming the courts, blaming the school, blaming the government...). What is done, is done, blame contributes nothing and just leaves bitterness behind.