I'm sorry that happened to you. I've had bad experiences in the last year with a stylist who was Deva trained and all natural and I know it feels awful to walk out feeling worse about your hair than you did when you walked in.
I've learned to speak up more for myself insofar as I will ask to see the ingredients on any bottle of product the stylist wants to put on my hair before allowing her to put it in, unless its a product I know and am ok with. If I don't like the ingredients, I'll tell her to use something else, and I have approve that product first too. I don't really care if they think I'm high-maintenance.
As for the comment that "there's no such thing as being protein sensitive," that's the biggest load of bunk. You can tell her, "really? well I know alot of curly girls who would disagree."
That stylist needs to rethink what she's saying; it sounds awfully like she wants to make a sale at the risk of costing herself not just a sale but a repeat customer, not to mention bad worth of mouth and other new customers who will be turned off by hearing about your experience. Maybe you could "tell" her that via a Yelp review? Use the tools you have at your disposal to fight back
I did that about my bad experience at a curly salon this year where the stylist made me feel like crap. I don't know if the stylist will read it, but I felt better anyway!
Glad your hair is recovering nicely!