It didn't poison us at all, it's meaningless. Not a single one among the millions of societally-damaging decisions made by companies in the pursuit of profit ever since that case, was made because of that case. A. It doesn't mean companies have to maximize shareholder wealth. B. Even in the scenario that it did, it doesn't set a time horizon for this maximization C. Anything can be construed as being good for companies in the long run. And this is why no company ever gets prosecuted for it - it's a total non-factor.

As I write this, you're right, it has poisoned us; it has mistakenly made a number of laymen believe that this is one of the reasons why greedy, evil psychopaths such as Mark Zuckerberg and tens of thousands of lesser known names, behave the way they do, that law is to blame for their decisions.