I think basically because if you keep just using conditioning shampoos and not DEEP conditioning it really isn't improving the condition of your hair. The proteins in deep conditioners when used with heat penetrate deep into the hair and grab hold. They strengthen the hair in this way. Cleansing and conditioning at the same time probably does no more than clean the surface and smooth the cuticle.
This is my understanding...I skimmed the book last night. I think deep conditioning and then using a conditioning shampoo is all right though...I hope so cause I LOVE Keracare Hydrating and Detangling shampoo.
ITA. I read her book and thought she was a goddess until I came here and found another 1000+ goddesses lol. Her book is a "stepping stone" to healthy hair IMO
Second'd. Her book was the first I read in like...8th grade? I was really fed up with my hair. I didn't have the money to buy any of her products tho, but i think her advice is good for someone just dipping their toe into the pool. Like you said, a "stepping stone". I respect her for opening my eyes and helping me realize anyone could have long, healthy hair with proper care.
LHCF just made that possible for me. without having to stick to a specific set of products at that.