The ultimate downfall of the Ammonite leadership is absolute. Uprooting them from their land is not merely a military defeat, but a complete exile of the entire ruling class. This harsh fate serves as a direct punishment for their severe cruelty and acts of robbery [אברבנאל].
The primary target of this exile is the king of Ammon himself [מצודת דוד]. However, his royal title carries a dual meaning, pointing not only to the human ruler but also to the nation's false god, Molech. The punishment sweeps away both the idol and the flesh-and-blood king. The royal princes are included in this fate alongside him to emphasize that the physical king himself is indeed going into exile [מלבי"ם]. This specific decree of a king and his royal court being marched into captivity together echoes similar prophetic warnings delivered by Jeremiah [רד"ק].