The wands. He had those now, and soon, if they told the truth, he would have Ginny safe. Then he could apparate her away from this place and reunite her with the rest of the family.
The creatures words were met with silence, as Harry followed. He did not care about the inhabitants, although he knew he wouldn't threaten any children. He was a father himself, for Merlin's sake. But he knew that it was useless to explain the suffocating, deadening fear to them. He wished it weren't. He swore to Dumbledore he wished he could make them understand without resorting to violence. But even he coud not put such a thing in words. To know, with every single death of a wizard or witch that the rest of the survivors were looking to him, and him alone, to avenge and save them. To know, with every death, that he failed.
Having them imprisoned by powerful entities, powerful enough to trap Ginny and prevent her from apparating....it brought back every terrifying moment. When Lucius had Hermione in the cellar; when Bellatrix hexed Sirius through the door; when Snape had sent Dumbledore plummeting over the parapet...Harry had failed. He couldn't stop his enemies then, either through ignorance or lack of skill or sheer stupidity, but he could stop Ginny from being taken from him.
He gave one last glance to those here before he disappeared up the stairs behind the creature. You read all about it, he thought, sadly, but you didn't live it.