Rabbi Moshe Grunwald zt"l of Chust, in his sefer Arugas Habosem, expounds on this topic. He explains that the Yidden's decision to refrain from gossip and slander in Mitzrayim was not merely a matter of avoiding negative actions, but part of a broader virtue that they possessed. Refraining from Loshon Hora was a natural outgrowth of their deep love for one another.
He cites a Ramban which questions how it is possible that while the entire Jewish population was enslaved in Egypt, they solely built structures and made bricks. If that were the case, the entire land of Egypt should have been completely full of dense construction projects after such a prolonged period of the Yidden's forced labor. The Ramban concludes that the Yidden were likely taken to work in shifts during their enslavement. Each group would work for a designated period of time, perhaps a month, while the others were free from labor.
The Arugas Habosem, however, raises a question. How does this explanation align with Chazal's teaching that due to the "קושי השעבוד", the extra hardship of the enslavement that the Yidden endured, they "completed" the time that they were supposed to be in exile, thereby shortening their exile period from the original four hundred years to only two hundred and ten years. If, according to the Ramban, most Yidden were not enslaved at all for most of the time, why does Chazal say that due to the difficulty of the enslavement the exile was shortened?
The Dividends of Achdus
The Arugas Habosem offers a profound answer to this question. He says that due to the close-knit unity amongst them, even the Jews who were free felt the suffering of their fellow brethren who were working during their shifts. So much so, that they felt the pain as if it were their own, for they were as one body. Thus, although not all the Jews were working at the same time in the literal sense, they were still unable to find rest as long as their fellow Jews were being enslaved. Their unity caused them to intensely feel their fellow Jews anguish and thereby accentuated their own suffering.