A valid perspective...
The way I see it, God created all that exists, including Satan, and since God is omnipotent, even Satan can do nothing that God does not approve. So why does God allow Satan to run around, messing everything all up? Well, I think that God's goodness could not be perceived unless there was a strong opposite, thus providing us with a choice. Even though the temptation for evil is always there, with discipline and devotion, we can come closer to God and learn more about His ways, as opposed to Satan's ways and thus become wiser and stronger in our faith.
I think it's always been this way, and I have a problem with God killing HIS children over something which they have no control over. It takes a lifetime to grow in our faith and make life choices and those kids were robbed of any opportunity to do so before they even knew that there WAS good vs. evil.