I find the argument, "If God is omnipotent, why doesn't he stop all human suffering" accomplishing nothing but limiting ourselves, and limiting God, let alone trying to say the result of God not stopping all suffering is proof he does not exist, else he would stop it.
What if it is not in God's purpose to end all suffering? Not yet. He will, ultimately, but you're not going to like the consequence of waiting for him to do it because the responsibility really always has belonged to us.
What if God is waiting for us to decide that we can stop it, ourselves? We can, and should. That happens to be our purpose, but we [some of us] continue to blame God when we know it is we, ourselves, who cause our suffering. We should not even be blaming Satan, because, after all, "the devil made me do it" is wrong, too. WE did it. We always have done it. We will do it unless we figure out our personal responsibility to stop it. Why is that so hard to understand? Well, first, because we [some of us] manage to convince others that God is responsible for everything that happens.
What if God is not responsible for anything but putting us here to work out our mutual problems by ourselves, just to prove we can.
What is stopping us from solving our problems? We look in it every morning, it it reflects nothing but our true nemesis: ourselves. We are to blame for the suffering we cause.
Why should we expect God to fix it for us as if we were helpless children? When are we going to decide to be the peacekeeping adults in the room?