Nice job. I have to use sulfate free shampoos for my curly hair to keep it happy. Actually, I don't even use shampoo on it. I just "wash" it with conditioner. It does make sense that they have different things in them for their different purposes. I'm glad you've answered this for questioning minds.
Thanks a lot, @apanamamama . I had been wondering for years for this subject.I thought it was time to learn the truth about personal care.