> It's basically saying there is an incentive to stop paying rent if the government will just pick up the tab.

Well, no, its not; its saying that if the government declares an eviction moratorium (which is extremely rare) without a rent moratorium, it might also, later, if finances ard convenient and it otherwise feels it expedient, retroactively decide to pay off unpaid rents before the end of that moratorium gets you evicted for unpaid rent.

(OTOH, the Fifth Amendment litigation already happening around the eviction moratorium itself might make that non-optional, anyway, and mooting that by providing full compensation now potentially saves the additional costs associated with litigation.)