At that very time there were some present who told him about the Galileans whose blood Pilate had mingled with their sacrifices.  He asked them, "Do you think that because these Galileans suffered in this way they were worse sinners than all other Galileans?  No, I tell you; but unless you repent, you will all perish as they did.  Or those eighteen who were killed when the tower of Siloam fell on them--do you think that they were worse offenders than all the others living in Jerusalem?  No, I tell you; but unless you repent, you will all perish just as they did."

We know that the wages of sin is death and all have sinned (Romans 6.23; 3.23).  Death has therefore spread to all because all have sinned (Romans 5.12).  It is therefore perfectly logical that we will each be destroyed unless we repent and believe in Jesus Christ.  It is only through Christ that we have peace with God, and this peace, this Christ, is God's free gift to us (Romans 5.1, 5.15, 6.23).  If we reject the gift and continue in sin (what we merit by nature), it is that rejected gift which we then must fear.  "I tell you, fear him who, after he has killed, has authority to cast into hell.  Yes, I tell you, fear him!" (Luke 12.4-5)

God's ways are not man's ways, his are infinitely beyond.  That does not stop us from applying our own logic to God.  We think that God punishes sin in this life through suffering, that each who suffers has sinned, and that the worse the suffering the worse the sinner.  Jesus says "do not think that they are worse sinners," but let their death be a warning to you: you will be destroyed if you do not repent.  And there is something far worse than earthly suffering and death.  "Do not fear those who kill the body, and after that can be nothing more."  (Luke 12.4)  That "more" is what concerns the one who persists in sin and does not repent in Christ.  Jesus said to the man he had cured by the pool "see, you have been made well!  Do not sin anymore, so that nothing worse happens to you."  (John 5.14)