Was there a “model release” clause in the contract you signed? I would imagine that most have a clause in their contract stating that. I could understand the confusion if their contract didn’t have that, and you asked for privacy after the fact. But if there’s a model release clause and you signed away on it, it makes sense that a photographer would have to charge more to make up for the fact that they will be unable to post any content from the session as a form of advertising or sharing.