> That is not an excuse for a corporation to rape and pillage the countryside, break any law, or behave in an objectively unethical manner.
The problem is that the laws that are relevant in this context are far from a static body. They are in constant flux as new behaviors, new knowledge and new technologies are adopted. This necessitates continous new rule making and new regulations that must be fit-for-purpose.
Shareholder profit maximization under current systems means it is rational (and a very profitable project) to proactively capture the political system. There is no meaningful penalty and eliminating the downside or creating more upside is enormously valuable (in monetary terms).
Instead of rule takers that must optimize profit within their designated sandbox, giant private entities become the unchallenged rule makers. This is not intrinsically and automatically evil. It becomes so whenever the monetary profit of a narrow set is grossly misaligned with the welfare of broader segments of society.
Examples abound. As they keep piling up they undermine the legitimacy of the very system. Killing the golden goose of a well governed market democracy and opening the door for uglier versions of society.