The sight of a ruined land prompts a profound realization among those who witness it. Passersby look upon the heavy devastation and recognize that the punishment is a direct result of a broken ancient covenant. The explanation given by these witnesses closely mirrors the warnings and prophecies of rebuke recorded at the end of the Book of Deuteronomy [ביאור שטיינזלץ].
The severe nature of this destruction is tied directly to the Exodus. God brought their ancestors out of the land of Egypt for a specific purpose. This event was meant to separate the Israelites from the rest of the world and place them under His direct supervision, rather than leaving them subject to the standard laws of nature, stars, and constellations. Because of this elevated relationship, their betrayal carries a much heavier consequence.
When they abandon their unique destiny and turn to idol worship, Divine anger intensifies and brings about unprecedented ruin. Such a disaster would not strike another nation for the same sin of idolatry, because other nations were never granted this direct, personal supervision to begin with, nor were they ever removed from the regular order of nature [מלבי״ם].