The impending destruction of Jerusalem was not a sudden event, but the result of deep, widespread, and intentional corruption. God's anger and the ultimate decision to ruin the city stem directly from the sheer scale and severity of the people's actions. The destruction is a direct response to the cumulative evil deeds committed by the nation over time [מצודת דוד].
What makes these actions particularly severe is the motivation behind them. The people did not stumble into wrongdoing out of a passing desire or a temporary lack of control. Instead, they acted with the explicit and deliberate goal of angering God [מלבי״ם]. Furthermore, this moral decay was not isolated to a few individuals. It infected the entire nation and completely consumed its leadership [מלבי״ם].
The spiritual guides who should have directed the masses were actually false prophets actively leading them astray [רד״ק, מצודת דוד]. This corruption reached the highest levels of society. The individuals driving the decay were not ordinary citizens, but the greatest, most respected, and most important figures in the kingdom, all of whom played an active role in the downfall of the nation [מצודת דוד, מצודת ציון].