Because corporations cannot be trusted to voluntarily protect the environment, they require regulation.
Evil. Corporations. Are. Evil.
Right. I hail from Western Oregon, which has been thoroughly denuded and rendered a blighted wasteland by Weyerhauser.
NOT! Corporations tend to grasp their symbiotic relationship with the market.
They can tend toward monopoly, and there is a reasonable regulatory role for government.
Just keep in mind that government, itself, is the ultimate monopoly.