How did the myth that soap is bad start?

After hours of Googling, I am pretty confident that soap free cleanser with surfactants were introduced during world war II due to shortage of oils to make soap.
All surfactants (SLS, ALS,etc) are known to cause alergic reactions & dermatitis in studies. Of course, the irritation can be reduced by adding moisturizers, humectants and other surfactants & it is eventually the entire contents that decide the irritation level. However, compared to soap; all surfactants irritate the skin.

Soap dries the skin & disturbs the ph balance of the skin. That can easily be remedied by adding moisturizers & humectants to the soap. Pears soap was the first mass produced Glycerin soap & probably is still the mildest soap out there. Also, all soap free cleansers have preservatives like Parabens & DMDM Hydantoin that definitely irritate the skin. Japan & Sweden have banned the use of DMDM Hydantoin in cosmetic products.

So, the question remains despite the ph advantage, soap free claims of surfactant based cleansers; soap is still a better and SAFER bet. It is bio degradable & non toxic to humans & animals. Does not pollute the water sources either.

So why exactly are soap free cleansers such a big deal & recommended by most dermatoligists ?