This passage concerns Jesus discussing the idea of "Did those bad people deserve what they got?" Apparently the people are asking Jesus' opinion of a horrible act of violence by Pilate (how about that for foreshadowing) against Galilieans who worshipped at Jerusalem, and the fact a tower collapsed near the pool of Siloam. They seem to be thinking perhaps the collapse of the tower was retribution for the massacre. But no one in particular caused the collapse. We call that a natural disaster. But these people had no frame of reference for natural. It was only God or nothing.
I fear we are often guilty of that same reasoning. Sadly some religious leaders have jumped on this and publically proclaimed that God was judging (fill in the blank). Today it is Haiti and Chile. Tomorrow there will be more disasters because that is the way the earth works. Plates shift, tornadoes rage, hurricanes flood, and blizzards freeze.
Jesus' message here needs to be our message. "Do you think that these Galileans were worse sinners than all the other Galileans because they suffered this way? I tell you, no! But unless you repent, you too will all perish. Or those eighteen who died when the tower in Siloam fell on them—do you think they were more guilty than all the others living in Jerusalem? I tell you, no! But unless you repent, you too will all perish."
We are all sinners. We all deserve death. Yet Jesus offers us forgiveness if we repent. All of us are in the same boat. We will all drown without the Lifesaver.