Being religious, I have given it a lot of thought. I lost my own mother when I was 15, and recall asking myself the same question. And again, when a house fire claimed two other dearly loved ones.So I got to thinking about it. And I think I may have the answer, though it does nothing to really soothe.
I think it is because God is so much wiser than us, and sees the "big picture" that we cannot, or will not, see.
From a purely scientific point of view, our planet can sustain not more than 20 billion people - or less. Limited space; limited resources. Now for the sake of argument, let us assume that when Jesus came, He put an end to pestilence and wars. Had none of those people died prematurely, and had they lived to a ripe old age and propagated, the world's population would have exceeded 20 billion over a century ago, and resources will have long been depleted. All countries - those that still existed - would all be "third world" in status, even America. There would be starvation and misery on a scale we cannot even imagine.
That said, any God would realize that there must be methods whereby the population is curtailed. He is our Father, and like any parent, He would not wish to have to choose which of His children would perish. So, he would make it so that "nature" - and our own lifestyle choices - would separate the weak from the strong - survival of the fittest. He would still know the sorrow of losing children, but at least He would not have to choose which of His children would suffer.
So He calls up the forces of war, pestilence, famine - just like it says in the Bible. Not to make us suffer, but to protect us from extinction. He is more concerned with the survival of Mankind than with the survival of any one individual.
Consider the Biblical passage that says "If thine eye offends thee, pluck it out; if thine hand offend thee, cut it off." Well, He is simply trying to teach us that in order for the whole to remain healthy, some parts must be sacrificed. It is simply a matter of survival of the fittest. Just as we prune trees and shrubs to make them healthier, or have our pets "fixed" to prevent being overrun, we, too, benefit from "pruning".
It is, in short, nature's way of helping us to preserve the whole - Mankind - though it results in losing individual parts.While this explanation does nothing to soothe our hearts at the loss of a loved one, it does explain the need, and indicates that God is not without compassion - He simply has to consider the survival of the whole of Mankind.
But perhaps this can help soothe - if any of the above has any credence, then there is a God, and those who suffer here and get called "home" before us are now in paradise, and will be patiently awaiting the time when we can all be together once more. Or, as Johnny Cash so aptly put it, "The Circle Won't Be Broken - we'll be together again up yonder in a little while."
And so there shall always be war. There will always be disease, famine, drought, poverty. And, lest we forget, we all grow stronger from any tribulation that does not kill us. Much as fire tempers steel, we must suffer the hardships of life if we are to become strong.