Hey OP, the real question is "why do you care?".
evolution is what evolution does.
we're just the lucky products of chance and happenstance anyway.
everything that happens is just the product of a bunch of atoms bouncing off of each other.
if you're an atheist/evolutionist/materialist and you feel even the smallest hint of sadness, grief, or sympathy for the children killed, you're borrowing from the Christian worldview and are not a true atheist/evolutionist/materialist.
if you do not feel even the smallest hint of sadness, grief, or sympathy for the children killed, then you are not only a true atheist/evolutionist/materialist, you are just as big a POS as the shooter.