There is no evidence at all that the Dominion was going to bother the Bajorans much or that they even considered them worth much effort.
You're wrong there. Don't forget -- in "By Inferno's Light," half a season before "Sacrifice of Angels," the Changeling Bashir attempted to blow up Bajor's sun in order to take out the allied fleet that stood in the Dominion's way. So Sisko wasn't lying. He knew
for a fact that the Dominion was willing to destroy Bajor altogether if it served their purposes. Given the strategic importance of the Bajoran system, as the bottleneck through which all Dominion fleets would have to pass to reach the AQ, it was likely there'd be massive battles there in the course of the invasion, and the Dominion wouldn't care if Bajor suffered collateral damage in the process.