The history of the Israelites is marked by periods of exile, but a deep contrast exists between their very first subjugation and those that followed. The primary approach among commentators is that a comparison is being drawn between the exile in Egypt and the later exiles under Assyria and Babylon to highlight the profound injustice and cruelty of the latter. When the Israelites first went down to Egypt, they did so of their own free will, seeking refuge and a place to live during years of severe famine [מצודת ציון, שד״ל]. Because the Egyptians hosted and sustained them, the Israelites essentially owed them a debt of gratitude. This dynamic makes the Egyptian enslavement a relatively lesser injustice, as the Israelites were the ones who originally crossed into Egyptian borders [רש״י, מלבי״ם, מצודת דוד]. Even so, the Egyptians still acted wrongfully by taking advantage of their guests, stripping them of their freedom, and forcing them into hard labor [רד״ק].
The later encounters with foreign empires present a completely different reality. The historical reference to Assyria encompasses both Sennacherib, who exiled the ten tribes, and the Babylonian king Nebuchadnezzar, who exiled Judah [רד״ק, מצודת דוד, שד״ל]. In stark contrast to the Egyptian experience, these empires forcibly removed the Israelites from their own homeland. They inflicted harm entirely for nothing, acting without any provocation, justification, or legal claim [רש״י, אבן עזרא, שד״ל]. Their actions were driven purely by wicked oppression and robbery [מצודת ציון, ביאור שטיינזלץ]. Although this period of exile was ultimately decreed by God, the conquering nations exceeded their mandate, acting with a level of cruelty that went far beyond what was required [רד״ק].
While most commentators understand this unprovoked oppression as harm inflicted for absolutely no reason, other perspectives explore the consequences of such baseless cruelty. One view suggests that the oppression yielded no true benefit for the conquerors. Instead of profiting, the Assyrian empire was ultimately destroyed during the days of Hezekiah and reduced to nothing [מלבי״ם]. Another approach notes that precisely because the robbery was so baseless, the subjugation could not last long, much like a thief who hastily grabs his plunder and flees [מצודת דוד]. Ultimately, this historical comparison creates a powerful logical guarantee regarding the future. If God redeemed the Israelites from Egypt, a land they entered willingly and to which they owed a debt, He will surely not abandon them to the hands of empires that violently robbed them of their freedom without any right or reason [שד״ל].