Even though the people have left their God, their God continues to uphold his covenant. In this case, it is the God of judgment who prevails rather than the God of mercy. The reasons will be the actions of the leaders of the community who have led people astray and not lived up to their social covenants.
Isaiah often chastises the oppression of the powerful and wealthy over the poor, and he brings that theme into this judgment. Thus, the princes of Israel are condemned for unrighteously profiting from the labor of the poor. In Isaiah’s poetic language, the poor labor to provide, and what they provide goes rather to the princes.
The non-egalitarian division extends to the way the powerful and wealthy treat the less fortunate. They grind them to pieces with labor for the benefit of princes, while keeping the less fortunate poor.