They were the right words to counter Lasciel and strictly speaking right from Uriels point of view but Mab was not wrong either.
How so? Because all indications Ive seen (text and WOJ) is that she was very much mistaken. Not a bad thing, she's allowed to misunderstand Human Nature, supposedly that part of why she used Sarissa as a forced-BFF giving her Human Cultural Interaction lessons.
You don't catch Uriel that easily. Since when is actually being well informed part of the human free will experience? Sometimes you get the idea that knowing everything leaves you no choice so no free will. It was her choice to drink something from a wizards lab.
She was aware that it was a Dangerous place and Chose to go Anyway; Harry was aware that he was hiding the full scope of that danger from her, but did it Anyway out of misguided protectiveness (by his own current evaluation). Fair Play from a Free Perspective.