Rebels often look at God as unjust, because in their eyes, their lives are extremely valuable, their sins are extremely trivial, and the gap between the two is too great for God to justify punishing sinners. To such people, I ask if that same logic can be applied to insects?
Now, for sake of transparency, I want to admit that my own answer is yes. Not to the same extent, but in my eyes, life, even the life of an insect, is precious, and so I hate needless killing. But let's be honest here, this opinion is mine, and mine alone. A lot of people will not hesitate to kill a spider for the sole "crime" of existing. If a fly buzzes too loudly, it is swiftly swatted to death. And let's be honest here: If a wasp stings us, its number is up.
Now, the crimes of an insect really are trivial. Is the spider harming you? Is the fly more than a mere annoyance? A wasp's sting may hurt, but it's temporary, whereas the death of the wasp is permanent. Yet, no one sees these deaths as murder. Heck, as a species, we're omnivores. We eat things that are more significant to us than a tiny invertebrate that crawled up our plug hole. If we judged all killing as murder, we'd all be in jail.
Now get this: Biblically speaking, the distance between God and man is far greater than the distance between man and an insect. In truth, the distance between you and the bacteria you wash off your hands is smaller than the distance between God and man. The Psalms ask "What is man that You are mindful of him, And the son of man that You visit him?" (Psalm 8:4). To God, we are mere grasshoppers (Isaiah 40:22). We are no more significant to God than an ant that bites our hand, and pays with its life. Why, then, should God view our lives as so significant that He should never punish us ever? God has more right to destroy us than we have to destroy a biting bug.
That's what makes it so amazing that He has so much love for us. While we are the bugs that bite His hands, He practically became a bug Himself, only to be swatted on our behalf, then get unsquashed so we could become human. Can you imagine, if such were physically possible, an actual human showing such grace to an actual bug? And yet, when God shows us that grace, we have the cheek to turn around, bite Him again, then complain that the bite is too trivial to be worth our lives? The hubris of the human race knows no bounds. We can be grateful to God, neither does His love.