I once saw videos of a group of people dancing and singing because another group suffered a calamity. Unlike them we should be very careful about assuming calamities are God's judgment upon People.
Calamities can be of two types: those which God generates (as a tornado), and those which men generate (as in the Twin Towers.)
A “Calamity” is different than a “Judgment”. Calamity happens to the guilty and innocent alike. It is more generalized, far reaching, than a judgment. It seems to cover much more area than a peoples' transgression would warrant. A calamity is like a tornado destroying a whole town rather than a specific household.
Judgment is what happens to those deserving punishment for wrong-doing. Judgment is targeted specifically toward the sinners and not the innocent about them.
Feeling of glee for the misfortunes of others is itself a sin. It is bad, perhaps dangerous, to have happy feelings when something bad happens to someone you do not like. "... and he that is glad at calamities shall not be unpunished." (Prov 17:5b)
The Twin Towers were a “Calamity” to us but a “Judgment” to the thugs who perpetrated it. Under our law and under the international law, what these thugs did was a crime, not a judgment. What we know is that God will have the ultimate judgment, maybe not at a time we desire, but it will be at the perfect time and it will be a perfect judgment.
We should hope that God's judgment will turn the wicked toward righteousness and that God will get glory from pulling diamonds out of the ashes.
