New Wash is quite different from co-washing products such as WEN. Neither has detergent and neither foam, but the similarity ends there. The biggest difference is that they may contain silicone that can build up to make hair lank and clog follicles. New Wash does not.
A word about co-washing: Using conditioner alone to “cleanse” is problematic because there is no cleansing happening; it will build up over time, make hair feel heavy and greasy, and may clog follicles resulting in sub-optimal hair growth. In addition, a detergent-based product is still necessary on occasion. Many co-wash products on the market contain some variety of detergent.