Why clothing companies poison us

https://www.theguardian.com/sustainable-business/2017/jun/13/hm-zara-marks-spencer-linked-polluting-viscose-factories-asia-fashion

By researching in to clothing companies I found there is a lot I don't know about, where my clothes come from, or where my clothes were made?  Factories are using chemicals in the process of making clothes for H&M, Zara or Mark and Spencer. They don't inform their customers about the chemicals on their garment labels, because I think if it's affects your health you need to know what are you buying and the companies should make you aware.