Kids die of shooting why's the reaction so muted?

Look at it this way. If every day in your neighborhood, somebody got into your garbage can and threw garbage all over the place, you'd eventually either go insane or just start accepting it as a part of life.

I recognize that murdering dozens of children is far from the same thing as somebody going through your trash, but it happens so often that we kind of go numb to it as a survival response.