I don't think there's such a thing as a toxic chemical versus a non-toxic chemical. All chemicals are toxic, even water. If you drink four litres, you would die of water poisoning. Everything is toxic, but it's a matter of degree.
You have to have a surfactant in a surfactant, or it won't work without it. If you have a surfactant in there, how toxic does it make that formulation? How much toxicity is being introduced into the environment by using that shampoo compared to another shampoo? The way you evaluate this is through a life-cycle analysis. You can't evaluate just by saying per compound, per gram, how toxic is it. You have to look at the formulation to get an assessment of the environmental impact.