Hey Glib!
Sodium lauryl sodium and the other lauryl sulfates are basically detergents used in shampoos to remove dirt, oils, debris, etc. Problem is, they work a little to efficiently at that. They'll remove natural oils-- and textured hair types need that to remain pliable, soft, and supple. Especially near the ends.
Generally if your shampoo is making your hair feel squeaky clean- its too harsh. I know most of us expect that squeaky feeling or we feel that our shampoo isn't working, but squeaky clean and textured hair means parched tresses. You have to leave some oil/conditioners behind on the strand and moisturizing shampoos should help you do this. They can't if there are too many stripping sulfates in the formula.
These stronger shampoos are great for oily hair types, typically straighter hair types--- but our textured hair needs something much more gentle for cleansing. Good moisturizing shampoos won't contain these sulfates. Clarifying shampoos will contain multiple sulfates because their sole purpose is to lift away EVERYTHING from the shaft.
Now, not all sulfates are created equal. There are the "laureth" sulfates are gentler than the lauryl sulfates, and the tricideth sulfates and myreth sulfates are gentler than both of those. Sodium is gentler than the ammonium sulfates, etc.
To counteract the effects of these shampoos you can either dilute them with water or add your favorite oil or conditioner to them. You could also deep condition your hair really really well to help put back some of the conditioning agents on the strand, but I think starting off with a gentle cleanser is really the best thing to do in the first place.
Harsher shampoos can lift your cuticles and rough them up badly. That's also why these strong shampoos tend to leave the hair feeling tangly. All of those cuticles are catching on one another and aren't smooth--- its tangle city after those shampoos.
Your deep conditioner will have to work overtime to correct that.
HTH!!!