Using too much soap dries your skin. So then you moisturize to make up for it, increasing consumption and pollution when just using less soap would accomplish the same thing without the drawbacks.
It is quite hard to tell what amount of soap is too much - it's very individual, because types of skin and the levels of their oiliness/dryness differ greatly. Someone with a dry skin can think everyone is using way too much soap, while a super-oily skin person can think other people's hygiene is somewhat lacking.
I was thinking more along the lines of "everybody uses more soap than they, specifically, need to". We're taught to completely remove the outer layers, wven exfoliating the skin in some cases. That's too much regardless of where your starting level was.