Slaughtering people will not change anything; brutality does not belong in humanity.
Those who were killed, whatever the reason, are lost. Lost lives cannot be replaced.
The injured see their lives turned upside down, their projects knocked over, suffer from wounds that may never heal.
And we, the relatives, the friends or other, we are all aggrieved, disconcerted, sad, to note that some people make that choice to slaughter other people.
Each life is unique, and can't be replaced; humanity is the sum of all the lives. Taking a life away is like depriving humanity of one of its components, and it is intolerable.