This seems to be a verse no one wants to come to terms with, it's so clear that disasters are used as punishments and calls to repentance.
For those interested, from Haydock's Catholic Bible Commentary, 1859 edition on this passage:
Ver. 2.
Sinners, &c. People are naturally inclined to believe, that those who are unfortunate, and afflicted with calamities, must likewise be culpable and impious. The Jews were very much given to these sentiments, as we see in many places of Scripture; John ix. 2 and 3. Our Saviour wishes to do away with this prejudice, by telling them that the Galileans, who are here spoken of, were not the most culpable among the inhabitants of that country; shewing by this, that God often spares the most wicked, and sends upon the good the most apparent signs of vengeance, that he may exercise the patience, and crown the merit of the latter, and give to the former an example of the severity which they must expect, if they continue in their disorders. Neither can it be said, that in this God commits any injustice. He uses his absolute dominion over his creatures, when he afflicts the just; he procures them real good, when he strikes them; and his indulgence towards the wicked, is generally an effect of his mercy, which waits for their repentance, or sometimes the consequences of his great anger, when he abandons them to the hardness of their reprobate hearts, and says, "I will rest, and be angry with you no longer." (Ezechiel, Chap. xvi. 42.) This is the most terrible mark of his final fury. (Calmet)
Ver. 3.
This prediction of our Saviour upon the impenitent was afterwards completely verified; for Josephus informs us, that under the government of Cumanus, 20,000 of them were destroyed about the temple. (Jewish Antiquities, lib. xx, chap. 4.) That upon the admission of the Idumeans into the city, 8,500 of the high priest's party were slain, insomuch that there was a flood of blood quite round the temple. (The Jewish War, lib. iv, chap. 7.) That in consequence of the threefold faction that happened in Jerusalem before the siege of the Romans, the temple was every where polluted with slaughter; the priests were slain in the exercise of their functions; many who came to worship, fell before their sacrifices; the dead bodies of strangers and natives were promiscuously heaped together, and the altar defiled with their blood. (The Jewish War, lib. vi, chap. 1.) That upon the Romans taking possession of the city and temple, mountains of dead bodies were piled up about the altar; streams of blood ran down the steps of the temple; several were destroyed by the fall of towers, and others suffocated in the ruins of the galleries over the porches. (The Jewish War, lib. vii, chap. 10.)
Ver. 4. Or those eighteen, &c. The Almighty permitted these people to be thus chastised, that the others might be filled with fear and apprehension at the sight of another's dangers, and thus become the heirs of the kingdom of heaven. But then you will say, is another punished that I may become better? No; he is punished for his own crimes; but his punishment becomes to those that witness it the means of salvation. (St. Chrysostom, Concio. 3. de Lazaro.)
Ver. 5. Unless you do penance, &c. The Jews did not penance; and therefore, forty years after our Lord's Passion, the Romans came, and beginning with Galilee, destroyed this impious nation to its roots, and polluted not only the court of the temple, whither the sacrifices were carried, but the inner sanctuary, with human blood. (Ven. Bede)
Correction: Lk 13: 1-5