Data has been told not to communicate. Several times, with direct orders. His response? Accusing Picard of murderous intent! Picard should have phasered down the cybernetic asshole there and then, but all he does is quietly offer this failure of an officer one last chance to redeem his career. I have no reason to think Data's accusation would have had any basis in fact, and indeed his libel should be added to the list of charges.
Data is not accusing Picard of anything, merely asking a question. While his ethical programming may well cause him to ask if they are letting someone die accusing Picard of murder would be based in emotion, something that Data is not capable of.
It seems as if the girls plea does sway Picard, and its almost as if being asked for help gives him wiggle room to intervene. Which makes a sort of sense. Starfleet can ( and does) offer aid to those aware of them and will respond to requests for aid but otherwise have a non intervention policy no matter what.